The New Jake Peavy

Jake Peavy is about to join another team. Given Peavy’s status as the best pitcher on the market, the move makes sense for the Chicago White Sox. Peavy’s time with the franchise has been mixed. Early injuries defined Peavy’s first few years with the club. One of those injuries could define his career. Peavy ruptured a tendon that tied the latissimus dorsi muscle to his shoulder. The tendon completely detached from the bone. Peavy underwent the experimental surgery with no guarantee he would ever regain his form. While Peavy hasn’t come back the same player, it hasn’t stopped him from being effective.

Peavy had to alter his entire approach after his surgery.

	Fastball Velocity	Fastball Usage	Sinker Velocity	Sinker Usage	Change Velocity	Change Usage	Slider Velocity	Slider Usage	Curve Velocity	Curve Usage	Cutter Velocity	Cutter Usage
Pre-Surgey	93.57	33.33	93.80	23.29	85.26	6.56	82.78	13.68	78.48	4.08	87.34	19.05
Post-Surgery	91.42	40.94	91.49	10.54	83.65	10.97	83.03	11.92	79.65	9.83	86.50	15.79

Peavy’s velocity has dipped substantially on his hard pitches — fastball, sinker and cutter. While that might cause some pitchers to shy away from using their fastball, Peavy has done the opposite. Despite the decreased velocity, Peavy is throwing his fastball nearly seven percent more following his surgery. With the decrease in his usage with the sinker and the cutter, his hard pitches are down overall. Peavy has been able to compensate with more curve balls and change-ups.

Even though the surgery sapped Peavy of his velocity, it hasn’t impacted his control. Peavy’s ball percentage with all six of his pitches has gone down since the injury. The biggest gain has been with his curveball, which jumped from 46.20 to 35.60. That could explain why he’s made it a larger part of his repertoire in recent years. A big part of his success can be attributed to his increased ability to pound the strike-zone. He’s taken his strike-throwing to an extreme this year, with a 69.1 first-pitch strike percentage. Not surprisingly, his walk rates the past three seasons are the lowest of his career. The fact that Peavy has been able to improve his control following shoulder surgery is astonishing.

It hasn’t been all good, of course. Peavy’s become an extreme fly-ball pitcher since his return. He’s been trending down too, and is sitting at a career-low 35.2% ground-ball rate this year. The big issue with that is Peavy’s propensity for giving up home runs. It’s been a major problem this season, as Peavy has given up 14 homers in just 80 innings. Some of that has been poor luck given his high 13.1% home run rate, but he was also prone to home runs last season. Some of his struggles can be attributed to U.S. Cellular Field, which plays homer-friendly, but the increase in fly-ball rate makes it something to worry about.

That should impact Peavy’s value once he’s dealt, though only if he goes to a pitcher’s park. Peavy’s already shown how valuable he can be in one of the friendliest home run parks in baseball, so he shouldn’t see a huge decline even if he lands in another hitter’s park. Peavy has been a completely different pitcher since the surgery, but it’s tough to tell when looking at his numbers.