Jake Arrieta’s Argument for the Best Season Half Ever

Sunday night, Jake Arrieta came within sniffing distance of doing the almost unthinkable. By which I mean, Arrieta made a serious bid to hit two home runs. He also, at the same time, flirted with a perfect game against the Pirates, but that part is very thinkable. I don’t know how many times this year Arrieta has grabbed attention for taking a no-hitter or a perfect game deep, but it numbers somewhere in the “a lot”s, with Arrieta more or less existing on the verge of history. It doesn’t take a no-hitter bid to put him in that position — the bid is practically a foregone conclusion.

Eventually, Arrieta gave up a hit and put multiple people on base, but none of those people happened to score, Arrieta spinning another seven shutout innings. Two batters of a total of 22 reached, and one of them only did so because Arrieta did him the privilege of hitting him with a pitch. The outing was timed well, what with the Pirates being a rival of the Cubs. The outing was timed well, what with Arrieta in the running for the Cy Young award. And the outing furthered Arrieta’s case for maybe having the best season half that ever there was. However arbitrary season halves are, we’ve been splitting seasons at the All-Star break forever, and what Arrieta has done since the break legitimately defies belief.

The math: 14 starts, covering just over 101 innings. All of them have counted as “quality starts.” All but one, the Cubs have won, and in the loss they got shut out. Arrieta’s given up a dozen runs. Nine have been earned. He really has averaged less than a run allowed an outing.

For the sake of comparisons, we can make use of the Baseball-Reference Play Index. It makes everything that follows pretty simple. Let’s get started, looking for the best ERAs ever. I know we don’t love ERA, but that’s why this is a starting point. You can’t not acknowledge it somewhere. I decided to define a qualifying season half as one in which the pitcher started at least 10 games. I think it’s a good-enough cutoff, and now here’s a top 10:

Top 10 Season-Half ERAs
Pitcher Half Year IP ERA
Ferdie Schupp 2nd Half 1916 113.3 0.71
Walter Johnson 1st Half 1918 166.3 0.76
Jake Arrieta 2nd Half 2015 101.3 0.80
Dutch Leonard 1st Half 1914 149.3 0.90
Kris Medlen 2nd Half 2012 95.3 0.94
Roger Clemens 2nd Half 1990 92.7 0.97
Bob Gibson 1st Half 1968 160.7 1.06
Tom Seaver 2nd Half 1971 139.3 1.10
Pete Alexander 2nd Half 1915 178.3 1.11
Spud Chandler 2nd Half 1943 121.0 1.12
SOURCE: Baseball-Reference

Just starting with ERA, we find second-half Arrieta in third place. Baseball has taken place over many years! So, while Arrieta would have more company if his numbers were worse, instead his numbers are fantastic, and his peer group is small. I can’t speak to any players the search might’ve left out, perhaps because their data is incomplete, but consider this a post about statistics we know. No use involving players who don’t have full statistical records.

The obvious next step from ERA — raw RA, folding in unearned runs. That top 10:

Top 10 Season-Half RAs
Pitcher Half Year IP RA
Jake Arrieta 2nd Half 2015 101.3 1.07
Kris Medlen 2nd Half 2012 95.3 1.13
Roger Clemens 2nd Half 1990 92.7 1.17
Ferdie Schupp 2nd Half 1916 113.3 1.27
Tom Seaver 2nd Half 1971 139.3 1.29
Dutch Leonard 1st Half 1914 149.3 1.33
Bob Gibson 1st Half 1968 160.7 1.34
Bob Knepper 1st Half 1981 86.3 1.36
Johan Santana 2nd Half 2004 104.3 1.38
Jose Fernandez 2nd Half 2013 68.0 1.46
SOURCE: Baseball-Reference

Just by runs, now we get Arrieta in first. And many would argue runs are a better measure than limiting to unearned runs. You’ll see some recent years, here, because offense has trended down, and these numbers are unadjusted for context. But just consider the message here: by runs per nine innings, Jake Arrieta’s second half has been the best season half — that we know of — all-time. Emphasis on “all-time.” It’s not something that can’t be debated, but there’s no debating the significance.

Let’s leave these metrics behind, though. Let’s throw away a little bit of sequencing and look simply at how the pitchers have been hit by their opponents. I went into the numbers and manually calculated wOBA allowed, with help from ours Guts page. Though Baseball-Reference makes OPS figures available, I thought I might as well go to the next step. Another top 10:

Top 10 Season-Half wOBA Allowed
Pitcher Half Year wOBA
Jake Arrieta 2nd Half 2015 0.192
Ferdie Schupp 2nd Half 1916 0.192
Reb Russell 1st Half 1916 0.198
Clayton Kershaw 2nd Half 2015 0.202
Johan Santana 2nd Half 2004 0.202
Pedro Martinez 2nd Half 2000 0.203
Burt Hooton 2nd Half 1981 0.205
Greg Maddux 1st Half 1995 0.208
Sandy Koufax 2nd Half 1965 0.208
Joe Horlen 2nd Half 1964 0.211
SOURCE: Baseball-Reference

Once more, we find Arrieta in first. Now, he’s in first by the smallest of possible margins, but he does hold the tiebreaker over Schupp if you keep following the decimals further to the right. And Schupp had his second half literally a century ago. It’s true that, since the All-Star break, Arrieta has allowed baseball’s second-lowest BABIP. That’s partially fueling this, but then, there’s a difference between talking about true talent and talking about results. Since the break, Arrieta leads baseball in groundball rate. He’s among the leaders in soft-hit rate and hard-hit rate. He’s given up just two home runs. He hasn’t been hit hard, so why try to pretend otherwise? About that .192 wOBA — Giants pitchers this year have a .208 wOBA. So, there’s that.

Of course, I have to note that, in that same table, 2015 second-half Clayton Kershaw is fourth. This is a good award race.

Now one last table, introducing an adjustment of sorts. For every pitcher, I calculated wOBA allowed. We also have league wOBA, so I created a wOBA- statistic, dividing wOBA allowed by the league mark and then multiplying by 100. Our last top 10:

Top 10 Season-Half wOBA- Allowed
Pitcher Half Year wOBA-
Pedro Martinez 2nd Half 2000 59
Jake Arrieta 2nd Half 2015 61
Johan Santana 2nd Half 2004 61
Ferdie Schupp 2nd Half 1916 62
Greg Maddux 1st Half 1995 62
Reb Russell 1st Half 1916 63
Clayton Kershaw 2nd Half 2015 64
Pedro Martinez 1st Half 2000 65
Burt Hooton 2nd Half 1981 65
Nolan Ryan 2nd Half 1986 66
SOURCE: Baseball-Reference

Pedro basically had to take the lead. Though his wOBA allowed that half-season was 11 points worse than Arrieta’s, the league wOBA now is 27 points lower than it was when Pedro was going to work. So the adjustment allows Pedro to vault out in front. I wouldn’t consider it an insult to argue that Arrieta might be having a slightly worse half-season than Pedro Martinez had at his peak. Arrieta, of course, is second here. Further adjustments would rearrange the table — I could split up the AL and NL wOBAs. Pedro was in the AL; Arrieta is in the NL. I’m also not considering park effects. You can’t adjust for everything, and sometimes it’s okay for a stat to be imperfect. All the stats are imperfect. By just about any imperfect stat you look at, Arrieta is having an all-time season half. If not the very best, then one of them. And there has been an awful lot of baseball.

If the schedule keeps up, Arrieta gets one more go. According to the Cubs website, he’s to be the Friday starter against the Brewers. Arrieta, naturally, is going to start the wild-card game against the Pirates, but that isn’t scheduled until October 7, which would put Arrieta on regular rest. So there’s one more chance for him to boost his numbers. The outing will probably be abbreviated, but it’ll bring an end to his second half. It’ll set the numbers in stone, and then we’ll have an even better idea of how this season half compares to all the others.

But it’s enough to say: it compares really well. It’s been a historic half season. And we split the numbers at the All-Star break. Arrieta pitched against the White Sox the Sunday before. He allowed a run and two hits in nine innings.



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Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.


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Jaack
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Jaack
7 months 26 days ago

I know this is not the take away from the article, but what was up with the Washington Senator’s defense in 1918? From the looks of it, at least HALF of the runs Walter Johnson allowed in the 1st half were unearned (he goes from 2nd on the ERA list with 0.76 to not even in the top ten of the RA list).

I mean, part of it was the era (not ERA), but Schupp doesn’t have the drastic shift that Walter Johnson did.

Nathaniel Dawson
Guest
Nathaniel Dawson
7 months 26 days ago

Gloves that were more like mittens. And fields that were more like your neighborhood vacant lot.

joser
Guest
joser
7 months 26 days ago

Well, the Wikipedia entry on Griffith Field (quoting a book about the man it was named for) mentions “…the unkempt field that can be seen in photographs of Griffith prior to 1923.” (The quote in the book specifically refers to the infield.) So that could be part of it.

And part of it could be the official scorer, which in those days was typically a newspaper reporter with fairly wide latitude in how the scored plays. Maybe he (it was usually a he, but not always) was hard-nosed about what constituted normal fielding plays and awarded a lot of errors; maybe he just liked the pitchers. Looking at the pitching staff on that 1918 team, all of them had a difference between raw runs and earned runs of 20 or more. And that wasn’t a one-year thing: Walter Johnson’s B-R page shows he had a wide gulf between runs and unearned runs for several years in the late teens.

And it definitely seems to be a home field thing: just looking at 1918, and summing up the difference between runs and unearned runs, Johnson had a delta of 16 at home and just 9 on the road, so clearly it was something to do with playing in Washington, though that doesn’t tell us if it was the park or the scorer.

Bat
Guest
Bat
7 months 26 days ago

People keep talking about the NL Cy Young award as if it is a three horse race between Arrieta, Kershaw, and Greinke.

But I think the winner will be Arrieta in a landslide because he has the following:

(1) the second half narrative (a compelling story, so to speak);
(2) 20 wins;
(3) a no hitter; and
(4) various advanced statistics that support his case as the best pitcher.

Sure, on this site 20 wins might not be what authors and readers of Fangraphs use as voting metrics. But that still matters to most of the voters quite a bit. Not as much as in the past – King Felix won with a 13 win vote total in 2010 – but if the voters see a guy who has a strong narrative, good traditional stats (i.e., 20 wins, no hitter), and is at the top near the advanced statistics, I don’t think Kershaw and Greinke come close to winning.

The two of them will get a few first place votes, but they’ll be also rans at the end of the voting, I think.

tomhaywood
Member
tomhaywood
7 months 26 days ago

You are correct. It will be Arrieta first, Greinke second and Kershaw third I imagine. The two Dodgers should probably be the other way round though.

CircleChange11
Guest
CircleChange11
7 months 25 days ago

Not just that, but there’s …

[1] The Cubs good team record.
[2] The Cubs exciting playoff story.
[3] Greinke and Kershaw splitting votes because of being on the same team/region.

These aren’t primary reasons … but the primary reasons are so close that other reasons start to matter more than usual.

xx
Guest
xx
7 months 24 days ago

I mostly agree with you, with the caveat that Kershaw could pull off an upset if he pitches again Sunday and hits 300 K. Even if an extra 6 Ks are tiny compared to the ridiculous things he, Arrieta, and Greinke have been doing all season, voters seem to like big round numbers, and putting up the first 300 K season in 13 years might knock them over.

Anon21
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Anon21
7 months 26 days ago

Arrieta is amazing. But thanks also for the reminder of Kris Medlen’s 2012, a little echo of the Braves’ Maddux/Glavine/Smoltz era that was really fun to watch.

Brian
Guest
Brian
7 months 26 days ago

I’d forgotten how shocking it was that Medlen lost that wild-card game – a nice reminder not to assume Arrieta and the Cubs are a slam dunk in their WC game (particularly – assuming the Pirates are the other WC entry – when you factor in a crazed PNC Park, Gerrit Cole’s awesomosity, a superior Bucs’ bullpen, not to mention good old random variation). Don’t get me wrong – I expect Arrieta to win any single game these days, but I think treating it like it’s a done deal undersells what he’s up against.

Phantom Stranger
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Phantom Stranger
7 months 25 days ago

That half-season by Medlen in 2012 is the closest I’ve seen any pitcher throw like Maddux for an extended stretch. It was like Maddux’s ghost had possessed Medlen that year. I laugh when people compare Greinke in 2015 to Maddux’s style.

Zack Moser
Guest
7 months 26 days ago

“All but one, the Cubs have won, and in the loss they got shut out.”

More incredible way of saying this: in the only Arrieta start the Cubs have lost in the second half… they got no-hit by Cole Hamels.

Ferdie Schupp
Guest
Ferdie Schupp
7 months 26 days ago

This Arrieta guy is pretty good.

Hurtlocker
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Hurtlocker
7 months 26 days ago

I’m thinking you blew out your arm Ferdie, one more great year and you were essentially done.

Jason B
Guest
Jason B
7 months 26 days ago

What did his manager say when he blew out his arm?

You should know. “Hurt?” (gestures) “Locker!”

(rimshot)
Guest
(rimshot)
7 months 25 days ago

!

Hurtlocker
Guest
Hurtlocker
7 months 25 days ago

Exactly, now you’ve got it.

Nick
Guest
Nick
7 months 26 days ago

Including the one run over 9 innings effort against the White Sox mentioned at the end would have actually raised the ERA of the sample. This is truly an incredible run he’s on.

tz
Guest
tz
7 months 26 days ago

He has made 19 quality starts in a row, allowing the opposition to score in just 10 of them:

http://www.fangraphs.com/statsd.aspx?playerid=4153&position=P&type=&gds=2015-06-21&gde=2015-09-27&season=

Mark Davidson
Member
Member
7 months 26 days ago

How about:

In his last 14 starts, opponents are slashing .151/.210/.211
Arrieta is slashing .211/.231/.368!

Mark Davidson
Member
Member
7 months 26 days ago

Just to piggyback on this idea; over the course of the season

Greinke
Allowed: .187/.231/.278
Hit: .234/.242/.359

Bumgarner
Allowed: .223/.263/.341
Hit: .240/.269/.467

CubbieBlue66
Member
CubbieBlue66
7 months 26 days ago

Starting from the date of August 4th, he’s given up 4 ER in total over 11 starts.

Every other pitcher in the top 50 in fWAR has given up at least 4 ER in a single outing since that date (with the exception of AJ Burnett, who spent a good chunk of that time injured).

tz
Guest
tz
7 months 26 days ago

Since the start of July, Arrieta has been worth 7.2 RA9-WAR. For a guy whose Hard% is second only to Keuchel, this might be as meaningful as his fWAR.

tz
Guest
tz
7 months 26 days ago
Dave
Guest
Dave
7 months 26 days ago

Best half in history: Pedro, 2000, 2nd half. In the #8 spot: Pedro, 2000, 1st half.

Also, Arrieta keeps leading (or close) in these measures, but Kershaw’s 2nd half keeps popping up too! And it is possible (likely?) that neither will win (or possibly deserve) the CYA!

Baseball!

tz
Guest
tz
7 months 26 days ago

On the subject of closing out the 2015 season, what’s the record for consecutive winless starts by a pitcher whose ERA and FIP are both better than league average over the streak?

http://www.fangraphs.com/statsd.aspx?playerid=10197&position=P&type=&gds=2015-05-23&gde=2015-09-27&season=

Captain Tenneal
Member
Captain Tenneal
7 months 26 days ago

What date do they use for splitting seasons before there was an All Star game? Just sometime in the middle of July? Only asking because I’ve never really thought about it before.

Turd in Punch Bowl
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Turd in Punch Bowl
7 months 26 days ago

He and Votto can win all of your post-ASB awards :D

Otter
Guest
Otter
7 months 26 days ago

It’s an insanely great run he’s on. What’s also nuts is it’s not like he’s had a huge spike in K% in the second half, it’s up ever so slightly (as are walks interestingly enough). It’s the ground ball rate, up 12 points from the first half, which explains pretty much it all (other than some luck).

dtpollitt
Member
Member
dtpollitt
7 months 26 days ago

Jeff Sullivan I don’t know how much you get paid but it should be more.

joe
Guest
joe
7 months 26 days ago

Is Arrieta the only one on every list here?

Eamus Catuli
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Eamus Catuli
7 months 26 days ago

Jake for CY Young!

SamF
Member
SamF
7 months 26 days ago

I love how both halfs of Pedro’s 2000 season are in the final table

Yirmiyahu
Member
7 months 26 days ago

And it’s not adjusted for league or park.

Anon
Guest
Anon
7 months 26 days ago

Over this incredible 2nd half run Arrieta is on still has fewer K (by a lot), more BB (by quite a bit), higher FIP (by quite a bit) and fewer WAR than Kershaw. After tomorrow, he will also have fewer IP than Kershaw (even though Kershaw was artificially cut short last outing) and will be further behind Kershaw in K and BB.

I will echo my comment in another thread – we keep inventing reasons not to acknowledge that Kershaw is simply the best pitcher in the majors and it isn’t even close.

Crazy old school thinking
Guest
Crazy old school thinking
7 months 26 days ago

because context does matter

Mike
Guest
Mike
7 months 26 days ago

Wow, cherry picking at its finest. I wasn’t going to comment, but I kept reading, and it only got worse.

You say fewer K by a lot. I don’t think that 120 compared to 106 is a lot but maybe that’s just me. He does have quite a bit more walks but since his WHIP is lower, which you didn’t mention, I’ll give him a pass. I do think that the fact that Kershaw’s ERA is 85% higher than Arrieta’s is a lot, however. Don’t know why you left that one out.

You mention FIP but FIP is a very imperfect stat as evidenced by the fact that, for the year, Greinke’s FIP is higher with the same defensive player, but yet he has let in far fewer runs. Maybe FIP is a decent predictive stat, but since there is only one start left for each player, predictive stats don’t matter. Especially when it comes to voting or determining who had the best half season.

As for WAR, I seriously question that Kershaw’s is higher than Arrieta’s in the 2nd half. Fangraphs has a higher WAR for Kershaw for the year, but other websites (ESPN, Baseball Reference) disagree with Fangraphs while agreeing with each other. Other websites do not split WAR in two, however. I think that the fact that Arrieta has won 2 more games in one more start with less runs, hits, home runs, etc. speaks for itself.

As for your statement about fewer innings pitched, even if Kershaw pitched a complete game last outing he would still have less IP than Arrieta. Arrieta last outing was also artificially cut short BTW. They both have another start left anyway so this point is moot. I did think that your statement that Arrieta would be further behind Kershaw in K and BB was funny though, as if Kershaw will get negative walks or something.

And lastly, everyone has acknowledged that Kershaw has been the best for the last 5 years. Have you been living under a rock? This article is only meant to point out that Arrieta’s 2nd half has been possibly the best of all time, nothing more. Very few unbiased people would agree that Kershaw’s has been better.

Otter
Guest
Otter
7 months 26 days ago

Don’t think anyone said Arrieta’s better. Just that he’s having a great second half fueled by more ground balls and a unsustainable BABIP and HR/FB rate. Kind of like Greinke…

Doug
Guest
Doug
7 months 26 days ago

You didn’t mention that Arrieta has a +12% groundball rate.

Weird.

TKDC
Guest
TKDC
7 months 26 days ago

I could qualify this with that I’m being a bit of an ass (but I won’t), but you say Arrieta has one more start to improve on these numbers, but the more likely scenario is that he regresses. It’s highly unlikely that he (or anyone else) is actually this good, so chances are better these numbers all bump up a bit (though the Brewers are terrible, so who knows?)

Also, how are halves measured pre-ASG?

swingofthings
Member
swingofthings
7 months 25 days ago

I think his point was that he has an opportunity to improve them, not that he definitely will.

CircleChange11
Guest
CircleChange11
7 months 25 days ago

All these Cardinal articles are getting annoying.

Dave
Guest
Dave
7 months 25 days ago

Ferdie Schupp?!? Hmm…. gotta look him up – the rest I’ve heard of.

Eric Martin
Guest
Eric Martin
7 months 25 days ago

Arrieta has faced tougher opponents than Greinke. Not only does Arrieta have 3 more wins, but the combined winning percentage of the teams Arrieta has beaten is better than those Greinke beat. The average W/L percentage of the 21 teams Arrieta beat is 0.5116. To put this in perspective, this would be a 83-79 record over a 162 game season. In contrast, the average W/L percentage of the 18 teams Greinke beat is 0.4770 (equiv. to a 77-85 season record).

Therefore, Arrieta’s more wins were against tougher teams. This also probably explains the slight differences in ERA and WHIP for Arrieta v. Greinke. In fact, in all games each pitcher has appeared (regardless of W, L or no decision), Arrieta’s opponents have a 0.5124 win % (83-79) and Greinke’s are 0.4856 (79-83). Greinke’s ERA and WHIP numbers are slighter better because he was facing weaker opponents.

Bip
Member
Member
Bip
7 months 25 days ago

wrong site for W/L analysis bud. Arrieta didn’t beat any of those teams, the Cubs beat those teams with Arrieta on the mound to start the game, a not-insignificant difference.

art
Guest
art
7 months 24 days ago

Well AZ and CO actually lead the National league in runs scored and the Giants are about equal to the Pirates in that regard. So I would think that Greinke and Kershaw are facing better offenses. I don’t think wins mean that much when the Dodgers bullpen couldn’t hold leads. Wins are a team stat. If W/L record is important, then Greinke has a better win percentage and has lost only half what Arrieta did. In the end I think the award will go to Arrieta or Greinke with Kershaw third in the voting. All three have had amazing seasons(average for Kershaw). Greinke had a great start and really hasn’t done anything to lose his lead in this race, but the other two have had great second halves and somehow managed to catch up. Either one is deserving. And it probably really will come down to the final start for each. The way they have pitched, I don’t see this decision becoming any easier.

Charlie
Guest
Charlie
7 months 25 days ago

Good stuff, Jeff. Cubs Related just wrote about a release point change with Arrieta, particularly how consistent it has been. Some might find this interesting: http://www.cubsrelated.com/2015/09/jake-arrieta-recently-got-even-better.html

Dave42
Guest
Dave42
7 months 25 days ago

Another non-saber stat that voters may consider – Kershaw will likely get 300 strikeouts this season. And while Arietta has been on an incredible 2nd half run, it’s not a half-season award. I don’t think you can make a bad choice. Kershaw may lose only because Arietta represents “new blood” and Greinke draws votes away.

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