The St. Louis Cardinals got Jake Westbrook at the 2010 trade deadline, and he performed well enough down the stretch to earn a 2-year contract with a mutual option on a third year. Last season he did not perform like the 2010 stretch Westbrook, though to be fair he did pitch to his career averages. What do we want to to see from Jake in 2012? More 2010 Westbrook, and less 2011 Westbrook, of course. How does he get there?
Westbrook historically allows a lot of base runners. Last year he allowed at least a runner per inning in his victories, and in his no-decisions and losses it was closer to 2 runners per inning. If Jake was not on his game it was obvious early; he only threw 43 innings in his 9 losses, and allowed almost as many hits, walks, and HR as he did in the 75 innings he threw during his 12 victories. Opposing hitters hammered him to the tune of a .368 BABIP in games he lost; in his wins, his BABIP was 100 points lower.
OK, if he pitches to less contact he’ll be more successful in 2012, right? It’s not that simple. In his 2011 losses, his K/9 was actually higher than in his wins (5.2 to 4.7), and in his no-decisions it was even higher. The year before they were virtually identical (5.3 to 5.5), although again his K/9 in no-decisions was higher. Striking out more hitters so there are fewer balls in play does not seem to be a key to Westbrook’s success.
So what can he change in order to return closer to his 2010 Cardinal form? Take a look at his Fangraphs page, specifically the pitch type section, for a possible answer. After the trade to St Louis Westbrook essentially ditched his cutter. He threw a fastball more frequently, threw his slider marginally more frequently, and threw his change-up marginally less frequently than he had while with Cleveland earlier in the year. In 2011, he threw his fastball slightly less frequently and his change-up with the same frequency as he had the second half of 2010. He made two major changes: he threw fewer sliders than in any year since 2007, and he threw more cutters than in any season ever.*
One has to wonder why the drastic change. Arm trouble? Inability to get a feel for the pitch that persisted most of the season? A lack of feel would make sense, because his slider got hammered (based on Fangraphs linear weights) throughout 2011 and no sane pitcher would consistently throw a pitch they knew could cause whiplash while watching it leave the home plate area.
It would seem the key to Westbrook’s success is his slider. It has been a crucial pitch for him throughout his career and had served him well up to last season. As we prepare for pitchers and catchers to report to Spring Training 2012, we need to watch Westbrook’s progress with his slider. If he has a feel for it, look for 2010-type performances this season, with 2011 game play a distant (and hopefully rapidly fading) memory. If he can’t find it again, maybe we can get Roy Oswalt back on the phone.
*Some of the change in fastball/cutter percentage may be due to refinement in the pitch f/x systems ability to detect the difference, however the change in how often he threw a slider cannot be explained away by a measurement software change.