Breaking Down the Decline of Chris Reitsma

Chris Reitsma finished the year in disappointing fashion. Though he was once the Rolaids Reliever of the Month (July), he just seemed to die down the stretch. He had a first-half ERA of 3.67 and a second half of 4.12. That’s no big deal, he was probably just DIPS lucky/unlucky in one of those halves, right? Now, Reitsma may have had a little bad luck on balls in play, and I certainly saw him allow some dink hits, but Reitsma’s problem seems to be a real one. And the decline can be traced back to a rainy July day just before the All-Star break, when Reitsma took a line drive to the rib cage from J.J. Hardy. I remember it well, because I was there with my father.

Lets look at his peripherals before and after the incident:

 		K/9    BB/9    HR/9
Before: 	6.1     1.5     .22
After:     	4.0     2.0     .57
Season:    	5.2     1.7     .37
2004:    	6.8     2.3     1.02

The main difference is the strikeouts. They really just dried up on him. His peripherals are good, but not what they were, especially compared to last year. I think Reitsma pitched hurt the entire second half. Don’t worry, this isn’t one of those arbitrary starting point tricks. Here’s a graph of Reitsma’s strikeout rate as it changed by game. The vertical line marks the game he was hit.
Reitsma's slide

Because he was hurt he lost his strikeouts, which required the Braves to gamble on balls in play. And I have found some evidence that strikeouts are correlated with pitcher ability over balls in play. So, he may have been allowing more balls in play that had higher probabilities of falling in for hits.

There has been some talk that the Braves might not offer him arbitration. I think that would be a bad idea, given the present state of the bullpen. If he does have a rib injury it will heal before next season. Reitsma’s had some tough times, but I’m going to stick by him.

One Response “Breaking Down the Decline of Chris Reitsma”

  1. Wendy says:

    Maybe it was the line drive, but he pitched well for the rest of July. We were also told that he tweaked his hammy in August (when in August, I don’t know, but I think it was early). Which also happens to be when he started his meltdown.

    I can see the decrease in the K rates after the line drive, but if I have to attribute his decline to a specific injury, I’m going with the hamstring, simply based on timing.

    not a very sabermetric response, though 🙂