Final Pitcher ERA-SIERA Differential: The Potentially Undervalued

On Saturday, I took a look at the five pitchers whose ERAs were the most below their SIERA marks, which suggests that they may be overvalued in next year’s drafts. Today I will look at the opposite, the five pitchers whose ERAs were the most above their SIERA marks, which might lead to them being undervalued in drafts next season.

Brandon Morrow

There has been enough written, debated and speculated about Morrow’s two seasons in a row of significant SIERA underperformance. This year, it was mainly a low LOB% that inflated his ERA, while last year it was primarily a ridiculous BABIP. That’s a good thing, because at least we know it isn’t one metric he consistently posts lower than league average marks in, which would make us question if he just lacks that particular skill. Interestingly, his career BABIP is at exactly .300, HR/FB ratio just below league average at 9.2%, and LOB% a reasonable 70.8%. Yet, his career ERA is an underwhelming 4.37, compared to a more impressive 3.66 SIERA. xFIP likes him less though, as its 3.94 career mark tells us, and is likely the result of SIERA treating extreme fly ball pitchers better than xFIP. For a pitcher with his strikeout ability, his expected LOB% should probably be higher, so maybe he really does have slightly lesser skills in that department. However, he has only made basically the equivalent of two season’s worth of starts, so I think it is still too soon to know for sure if that is the case. His perceived value has likely hit bottom, so there’s no excuse not to take a shot again next year.

Derek Lowe

With reports of Lowe not opening next season in the Braves rotation, the team might want to remember what happened with Kelly Johnson not too long ago. The team chose not to resign Johnson after a disappointing 2009 season. But all they had to do was look at his .247 BABIP and realize it was just bad luck and he should rebound. And rebound he sure did in 2010. On the surface, Lowe looks done as a reliable starting pitcher, but his skills and expected ERA metrics have been as consistent as it gets (with the exception of 2009). Lowe has gone through patches with inflated BABIPs before and as an extreme ground ball pitcher, the defense behind him plays a huge role in his ultimate performance. I think the Braves would be foolish to just give up on him and fantasy owners, especially NL-Only ones, would be smart to take a cheap gamble no matter what his role is to open the year.

A.J. Burnett

Hmmm, his skills look very similar to the vintage Burnett we used to be accustomed to when he was posting ERAs below 4.00 each year. What really killed him was a crazy 17% HR/FB ratio, a level he has actually experienced once before back in 2007. The next year, his HR/FB ratio dropped right back down to a more normal 9.6%. Last season, Burnett’s skills were legitimately diminished, and though he did not deserve an ERA above 5.00, it was not a very good year. Now after posting an ERA above 5.00 for a second straight year, his perceived value is likely at an all-time low. Although I am somewhat concerned about his declining fastball velocity, he could yield a nice profit at little cost in drafts next year.

Zack Greinke

Aside from the awful Brewers defense hurting Greinke’s BABIP, he has had a history of posting above league average marks. In fact, he has not posted a mark below .303 since his rookie year in 2004. That may very well be a result of perennially poor Royals defense, or some lack of skill in this department or a combination of both. Besides the high BABIP, a 13.6% HR/FB ratio was problematic, but luckily he does not have a history of high marks here and his career rate is still just 9.0%. He led all MLB pitchers in SIERA, so he could be one of the few pitchers drafted as a team’s ace that actually yields a big profit.

Fausto Carmona

He pitched very similarly to last season, yet his ERA jumped from 3.77 to 5.25. He was absolutely lucky last year, but certainly did not deserve to suffer through regression to this degree. His poor strikeout rate will limit his fantasy value and he has had trouble stranding base runners in the past. With his extreme ground ball ability and a return to solid control, he should never see an ERA above 5.00 again. However, only AL-Only leaguers will really want to roll the dice as his upside just isn’t high enough to be worth gambling on in mixed leagues.

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Mike Podhorzer produces player projections using his own forecasting system and is the author of the eBook Projecting X: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. He also sells beautiful photos through his online gallery, Pod's Pics. Follow Mike on Twitter @MikePodhorzer and contact him via email.

11 Responses to “Final Pitcher ERA-SIERA Differential: The Potentially Undervalued”

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  1. Ryan says:

    Derek Lowe and the Braves are in a unique position. With their pitching depth, it makes more sense to just move him to the bullpen, as I expect Mike Minor to out perform his numbers next year (or Julio Teheran for than matter). Lowe’s Swinging strike percentage went up in 2011 due to his slider (weighted at 8.7). However, his sinking fastball was rated at -10. As a he relies on that pitch too much, it doesn’t make sense to give him a starting job when there are better alternatives. In a relief role he could be a sinker/slider pitcher with a great strikeout rate and help the team more in that role. His fastball doesn’t allow him to go through a lineup multiple times anymore.

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  2. Scott says:

    Jonathon Niese:
    4.40 ERA – 3.27 SIERA = 1.13 difference.

    He barely missed the cut for leaders in difference, but IMO is a much better option next year than some of these guys w/ bigger differentials. Watch out for him too on draft day.

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    • Mike Podhorzer says:

      Niese is a nice choice as well. Solid all around skills and should come rather cheaply.

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    • Mark says:

      Niese is an interesting case and someone to watch closely next year. On the surface, he seems like a guy who does everything well but nothing superbly. He has above average command and GB% with and average K%. His BABIP has been high, but that could at least partly be accounted for by the Mets below average defense, particularly on the infield (In 2010 because Reyes missed time and Castillo and Wright were below average, in 2011 because Davis missed time and the guys playing 2B besides Tejada were below average along with Wright again). Its unclear how the Mets defense will look in 2012 outside of Wright and Davis, who basically wash to average on the corners, so a lot will be dependent on who they have up the middle. He’s also tended to have a slightly high HR/FB, which is odd for a pitcher who pitches half his games in CitiField, as well as low LOB%, which is probably a product of the high HR/FBs and BABIPs.

      What’s interesting is that in 2011 Niese drastically improved his BB%, but he did it by using his curveball more, his cutter less, and throwing fewer pitches in the zone (Zone% was down, which makes sense with the reliance on the curve, though it was still above average). This is pretty unusual. He did it by getting a higher O-Swing% and maintaining his F-Strike%, but given all that, you’d expect his SwStrike% would have spiked as well. Instead, it stayed about the same and his O-Contact% went up. His LD% was identical to 2010 as well, which is also a bit odd considering more of his contact has been coming on pitches out of the zone.

      My theory is that he’s doing something to tip his pitches, particularly his curve but perhaps his cutter as well. He stopped relying on his cutter early in the year when he wasn’t getting good results on it and started using his curve, which was effective initially, but he would often start getting hit very hard the second time through lineups and when he had to face the same lineups twice in a short period of time. This could also account for the high BABIP and the steady LD% despite all the contact he was getting outside the zone. It seemed like once he faced a batter more than once, they would be able to sit on his curve and swing aggressively at it and were still able to adjust pretty easily to his fastballs. If he can rectify this, he might be even better than we expect, as his BABIP might normalize and we might see the SwStrk% and K% spike we expected with heavier use of the curve outside the zone when he’s ahead in the count. If he can’t though, he may remain a guy who underperforms his peripherals and posts another high BABIP year. Should be interesting to watch.

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    • Mark says:

      To follow up on this thought: If you look at Niese’s Pitch FX game charts compared to other pitchers, his release point chart looks much “cleaner” than a lot of other pitchers who rely so heavily on curves. Like most pitchers the release point of his curve is higher than his other pitches, but its much more clustered together in a sort of “island” that’s somewhat separate from his other pitches, and particularly in comparison to his cutter, which is clustered much lower. In 2010 the release point on his cutter seems a bit more deceptive as it tends to be a bit more centered around he throws his fastball, but in 2011 it drifts even lower. More importantly though, compared to other pitchers his curve is still consistently coming from a more distinct high release point. It becomes even more apparent when you look at the individual games. There’s typically quite a bit of white space between Niese’s curve release points and his other pitches. But if you look at other pitchers who throw a lot of Curves, while the release point tends to be higher, there’s not nearly as much white space between the curve release points and other pitches, and its especially extreme vs. Niese compared to his cutter, whereas when you look at other guys with curve/cutter or curve/slider combos the release points tend to be much closer together.

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  3. rempart says:


    Have you or anyone else ever studied how the top/bottom 10 or 20 pitchers in one season correlate yty across the different methods?

    Is SIERA better at predicting players at the extremes than say FIP,XFIP,tERA etc.?

    Thanks in advance. Love your stuff.

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    • Mike Podhorzer says:

      I think SIERA is better at predicting the extremes in terms of GB% and FB%. That’s where it has the biggest disagreement with xFIP and its methodology makes enough sense to me to believe it is the better metric for these pitchers.

      I have not performed any in depth study looking at the top and bottoms guys each year and how they performed the following year though. Maybe someone else has.

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  4. Abe Jaroszewski says:

    Brewers defense was not bad this year: average to slightly above average depending on our metric. Please stop perpetuating this myth.

    Think Greinke’s above average BABIP is he groves too many pitches. Someone with his stuff and consistantly above average BABIP isn’t all defense. Certainly that doesn’t explain ALL of his extra high BABIP this year, but its definitely a career-trend.

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  5. RC says:

    How is John Lackey not on this list? 6.41 ERA, 4.36 SIERRA.

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    • Manolo says:

      Guessing here … but I believe it’s because Lackey failed to reach 162 IP and therefore isn’t a qualified pitcher.

      That happens when a pitcher frequently is yanked in the 4th or 5th innings.

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  6. Manolo says:

    On Burnett …

    I’d stay away on draft day except in AL only and very deep mixed leagues.

    His zone % has plummeted to 40.2%. He threw 25 wild pitches and is regularly unable to find the strike zone. Blame his gopheritis if you wish as many other authors have pointed out that he’s been unlucky. However, but he’s almost in freefall when I examine his peripherals beyond SIERA, xFIP, ERA, etc.

    IMO, his HR tendencies stem from the complete inability to locate his pitches — forcing him to throw a cookie down the middle or accidentally putting a supposed-to-be corner pitch down broadway.

    There’s a lot to dislike about Burnett right now. I’ll admit he may make the necessary adjustments but I wouldn’t go near him on draft day.

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