Throw It Like a Ballplayer

providing baseball commentary and ponderings since April 2010

Jake Peavy: a Jekyll and Hyde Case Study

Posted by dannmckeegan on May 4, 2010


Jake Peavy delivers as a Padre. His pitches when with San Diego tended to make their way to the seats whenever he strayed too far from the Pacific coast. Photo from

There is nothing quite like a visit from the Kansas City Royals to cure what ails you.  Enter Jake Peavy, the nominal White Sox ace acquired by Kenny Williams in the middle of 2009.  Peavy had struggled with both his velocity and location this season up until Monday night’s start against an offensively challenged (and pitching-challenged and defensively challenged) Royals team.  Relying heavily on the newly regained zip on his fastball (94-95 at times), Peavy mixed in a cutter, curve, slider and change to the tune of only 4 hits and a walk through 7+ shutout innings.

This enticing outing for White Sox fans comes as concerns have been coming to a head.  Surprisingly, there has been little historical analysis to explore Peavy’s baseball past.  That is, sabermetric projections were happy to give Peavy’s potential a nod in the preseason, but nobody quite looked at what’s happened before.  Leave the predictions to Miss Cleo.  This isn’t about analysis, per se, but rather a take on the historical record.

Peavy has won a Cy Young Award (2007) and twice been an All-Star (2005, 2007).  Since debuting in 2002, Peavy has surpassed 200 innings in a season three times (2005-07) and started 30 or more games in four seasons (2003, 2005-07).  He left San Diego with a career record of 92-68, averaging 61/3 innings and 103 pitches per start.  His cumulative rate stats are impressive as well: 3.26 ERA, 1.182 WHIP, 3.10 K/BB ratio, and 0.667 opponent OPS all merit ace consideration in this day and age.  He clearly amassed the numbers and reputation of a top pitcher.

On the surface.

There was obviously some initial concern about the usual suspects: How would he move to the American League from the National?  How would he transition from the spacious PetCo Park to the hitter haven of U.S. Cellular Field?  Both were fair concerns, but no one seemed to do their due diligence in going beyond a cursory glance at his home/road splits.  Allow me to provide those numbers now.

Peavy's good starts

All of Peavy's Home and/or Friendly numbers...boy, does he love the Pacific Coast. Some fantastic numbers, without a doubt. In fact, they're a little too good compared to his overall numbers...

Averaging over a strikeout per inning and in possession of a WHIP barely over a base-runner per inning, Jake Peavy’s opponent OPS of .606 was actually lower than the .608 OPS Peavy tallied as a hitter himself in 2008. Former Mariners and Diamondbacks manager Bob Melvin, by way of comparison, had a career OPS of .604 during his 10-year career as a backup catcher. Of course, any set of stats this good requires the reality check of a look at Jake Peavy’s other numbers. With that in mind, here is a spreadsheet of what Peavy did when visiting his other three divisional opponents (Diamondbacks, Giants, and Rockies); his totals during all non-“Doctor Jekyll” starts; and how these tie in to his aggregate totals.

Unfriendly to Peavy

Notice Peavy's poor production at the home parks of his divisional rivals other than the Dodgers. The three parks are hitters' parks, generally, though specifically the NL West has been hit-or-miss offensively this past decade. Where his "good" numbers contain an OPS comparable to a backup catcher, his "bad" OPS is barely under .800. Not great.

Cumulative Numbers

There is a random component to all of this.   Certainly, Peavy has made excellent use of the resources offered him by the pitcher-friendly environs of Jack Murphy, PetCo, Chavez Ravine, and a few other parks. But he was pretty bad, generally, in the NL West’s hitters parks (the BOB, the Phone Book, and Coors). Furthermore, if we take those “Doctor Jekyll” starts away from his pre-2010 totals, we are left with some food for thought:

  • He loses 1/3 inning per start;
  • His ERA goes up 0.91 points, while his FIP leaps from 3.5 to 4.5;
  • He loses 0.75 K and gains .67 BB per 9 innings, with a K/BB ratio drop of 3.1 to 2.3;
  • The ball flies out of the park at a rate of 1.32 HR/9 IP, a leap of 0.4 from the 2002-09 total.

Three questions need to be answered.

First, among other elite pitchers of recent vintage, do any have such striking splits between their home and road, or pitcher/hitter park, splits?   Second, what pitchers contemporary to Peavy have overall numbers comparable to Peavy’s away from PetCo & Friends?  The third, informed by the answers we find to the first two questions, asks about money. What kind of money is Jake Peavy worth, and (3b) is his current contract (3 years, $52mm, $22mm option/$4mm buyout for 2013) worth it.

Here’s a list of pitchers who have been called aces, linked to their pages, and a Y/N if their numbers show similar splits to Peavy:

Player Yes No Player Yes No Player Yes No
Beckett, Josh x (NL only) Carpenter, Chris x (both leagues) Greinke, Zack x
Halladay, Roy x (exc. TEX and ANA) Lackey, John x (Pitcher/Hitter) Lee, Cliff x
Martinez, Pedro x Oswalt, Roy x Sabathia, CC x (rough in OAK)
Santana, Johan x Webb, Brandon x Zambrano, Carlos x

Some pitchers have shown some noticeable splits, but for the most part top-tier pitchers can maintain their level of home performance when they go on the road. Some parks – Arlington and the Bandbox, for instance – lend themselves to extremes, much as some pitcher parks will artificially deflate numbers. Some pitchers, like Pedro, have switched leagues without a problem. Surprisingly, Oswalt from Houston has had a noticeable split. My Oakland note for Sabathia simply points out that he struggles in his hometown, an odd but not unheard of trait. Peavy most closely resembles Red Sox starter John Lackey insofar as both show a spectrum of performance as closely tied to park factors as anything else.

As far as the second questions goes, who resembles the profile of the Mr. Hyde half of Jake Peavy? My first instinct was pretty close, and this guy seems even more appropriate because he is a former White Sox and current Padre. Yes, I am talking about Jon Garland. Go ahead and check out Peavy’s red numbers above, and then look at the table below of Garland’s overall career numbers:

Garland, Jon 4.37 ~6 1.387 1.1 1.6 3.0 .768 .288
Neagle, Denny 4.24 ~6.15 1.312 1.2 2.38 2.8 .750 .290

So we’re now at an important moment: was the kind of performance Peavy turned in tonight indicative of what the White Sox can expect from here on out? If it is, then Peavy’s contract will be money well spent. However, if he was simply beating up on baseball’s rejects with everything clicking, then there’s a large enough body of work for us to expect that Peavy will simply be somewhere in the middle. He became an ace in large part because his environment and his stuff meshed. The central question lies in his ability to adapt to a park and to a league where you want to keep the ball on the ground. He may well be able to do so and be an effective pitcher. But as we have seen in the past, pitching and real estate have a lot in common.

Location, location, location.

Jake Peavy’s history tells us that he gets average results outside of pitcher-friendly parks. There are a few of those in the AL – Detroit, Seattle, Oakland – but there are also a lot that favor power hitters and the home runs that have been Peavy’s big problem. One of those is his home field. The prognosis for the cure from the descent into Hyde, in truth, is not negative. Rather, it is simply more honest. He never quite was a Jekyll to begin with. He was very good, often among the NL’s best, but we still don’t know what that means.  One of the finer subplots of the 2010 season will be the unfolding of this story.


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