One thing that has been on my mind for a while is Chase Utley‘s power hitting against right-handed pitching before and after his thumb injury. As you may recall, Utley tore a ligament in his thumb that caused him to miss nearly two months of the regular season. Overall, Utley’s season was still productive but still below what we’ve come to expect from him. I wouldn’t go as far as calling it an “average to poor” season, as a Beerleaguer reader dared, but he was certainly not the same guy even after he was taken off of the disabled list.
Utley had a staggeringly amazing .434 wOBA against left-handed pitching this season, but only .337 against right-handers. It is quite odd that a left-handed hitter would have such a drastic platoon split in favor of same-handed pitching, but this is the case with Utley.
Here’s a look at Utley’s isolated power (ISO) against RHP before and after his thumb injury:
Before the injury, Utley essentially had tremendous power in the lower left quadrant of the strike zone, and even a little below. After the injury, if you split the strike zone into nine areas, Utley has lower-left and upper-middle for the most part.
The biggest change has occurred in his ability to handle breaking pitches. Here are the same two images as above, except we are only looking at “soft” stuff now:
The sample size for the top graph is 428 pitches; 257 for the bottom.
My theory is that Utley’s thumb is still a problem, sapping his power. Left-handed pitchers pitch Utley low and outside. Right-handers do as well, but pitch inside on a more frequent basis. Hitting inside pitches puts more pressure on the wrist and thumb given the direction in which the bat makes contact with the ball. Additionally, hitting softer pitches requires good bat control which is related to hand strength and dexterity. A thumb injury such as Utley’s will sap both attributes, which is why he has seen such a precipitous decline in his power hitting.
Data courtesy Baseball Analytics.