Which Strugglers Does SIERA Like Best

As hard as it is to concentrate with our fearless leader’s struggles on our minds, we must soldier on. Today, we’ll take a break from the National League outfield (don’t drop Nate Schierholtz until you know where Carlos Beltran will end up and what the Giants will do to fit him into the gargantuan holes in their lineup, since he could end up with the bigger part of the platoon with Cody Ross) to instead have some fun with the new statistic on our site. Yup, it’s SIERA time.

The thumbnail about SIERA is that creator Matt Swartz found that strikeout rate interacted with a pitcher’s BABIP and HR/FB. He also found that elite ground ball rates lead to better BABIPs. Because of these interactions, some pitchers should be compared to other excellent pitchers in those categories instead of being tied to the league average. We might find some aces that look better with SIERA, for sure, but it’s worth running the list in order to see who SIERA likes best. Another weapon in the fight against the luck dragon. Expect fabulous FIP-SIERA and xFIP-SIERA posts later in the week.


Fausto Carmona 5.14 2.69 12.90% 6.80% 0.286 5.63 4.84 0.79 3.93 1.7
Chris Volstad 5.98 2.75 15.00% 6.90% 0.32 5.58 4.46 1.12 3.91 1.67
Ryan Dempster 8.53 3.16 21.90% 8.10% 0.331 5 3.7 1.3 3.44 1.56
J.A. Happ 7.75 4.85 19.10% 12.00% 0.309 5.88 4.78 1.1 4.5 1.38
Ted Lilly 7.05 1.97 18.40% 5.10% 0.297 5.08 4.52 0.56 3.77 1.31
Bronson Arroyo 5.19 2 13.30% 5.10% 0.292 5.56 5.67 -0.11 4.27 1.29
Javier Vazquez 6.85 3.09 17.20% 7.70% 0.314 5.35 4.3 1.05 4.22 1.13
Jake Westbrook 4.88 3.33 12.40% 8.50% 0.308 5.04 4.44 0.6 3.98 1.06
Derek Lowe 6.08 3.26 15.70% 8.40% 0.307 4.49 3.49 0.99 3.59 0.9

There are the struggling pitchers that every advanced metric still likes. Call Ryan Dempster the spokesperson for this group. His bad luck has been stupendous. A .331 BABIP, 67.3% LOB and 11.6% HR/FB have all conspired to keep this man’s ERA inflated. It’s nice to see that SIERA and FIP agree that he’s been one of the unluckiest pitchers in ball. He should have an ERA much closer to three than to five going forward. The only real peripheral that is down this year is his swinging strike rate, and at 9%, he’s still above average. Well, okay, his fastball velocity is down, but the fastball has long been his worst pitch. He can survive a half-mile-per-hour drop there.

More interesting, perhaps, are the players that SIERA likes better than FIP. In particular, let’s take a look at Bronson Arroyo. FIP believes that he has deserved every bit of his poor performance this year. His 5.67 FIP, built on a 5.19 K/9 and 2.15 HR/9, is even uglier than his ERA right now (5.56). SIERA instead wants to give him the home run rate that his profile deserves, and is in line with his 4.19 xFIP. His worst full-year home run rate was 1.31 before this year, and even if Arroyo worsts that number for the season, he shouldn’t be any worse than that number going forward. Shave almost a full home run per game off of Arroyo’s line and he’s suddenly deep league worthy again.

What about Ted Lilly? Similar story, and this time SIERA goes further than xFIP, as Lilly has has decent career strikeout ability and is suffering through the second-worst home run per fly ball rate of his career. But do we love Lilly as much as SIERA does? He’s usually good for a high threes ERA based almost solely on his control and ability to mix his slider, curve and fastball well. This year, he’s got the same control (1.97 BB/9) and the same pitches, but the results are not the same. His swinging strike rate is below average for the first time in his career, but he’s also in the midst of a four-year decline there. His mix shows he’s using the curveball a little less, and he’s lost velocity again for the fourth year in a row (or more). Perhaps Lilly’s underlying stats can defend a pessimistic stance about his ability to recover this season.

With Derek Lowe and Jake Westbrook, SIERA likes the fact that the two pitchers have elite groundball rates. Both are over 60%, which is exponentially more impressive than being over 50%. When seen through the prism of our fancy new bauble, Westbrook’s .308 BABIP looks more unlucky than it might otherwise.

Yes, xFIP likes many of these pitchers about as much as SIERA. It will be interesting to see what the xFIP-SIERA list looks like.

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With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

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Dempster’s defense sucks; not sure if you can expect a league average BABIP for him, though I agree that it should come down. Also, is his “bad” HR/FB really just due to bad luck? Dempster hasn’t recorded a season with a sub-11% HR/FB since 2008 and Wrigley has an above-average park factor for HRs. LOB% does look flukishly low though.