Something’s wrong with Roy Oswalt. Everyone can see it, including those in both the traditional and Sabermetric crowds. Ever since he took a short leave of absence in late April (which was followed by a stint on the 15-day disabled list), Oswalt has not been the same. In his five starts prior to leaving, he had a 7.0 K/9, 2.3 BB/9, and induced swings-and-misses at a nine percent rate. In his five starts after returning, he had a 3.7 K/9, 2.2 BB/9, and induced swings-and-misses at a six percent rate.
The velocity on Oswalt’s fastball declined precipitously as well, even prior to his short time away from the team. Take a look at this chart from FanGraphs (click to enlarge).
Aside from the fastball, Oswalt’s other pitches are slower across the board as well. His average slider is down 0.7 MPH from last year; the curve is down 2.7 MPH; and the change-up is down 0.9 MPH.
Despite the discouraging trends, Oswalt was getting results. Going into yesterday’s game against the Chicago Cubs, Oswalt had a 3.05 ERA, tied for 21st in baseball among pitchers with 50 or more innings pitched. Meanwhile, his SIERA was less enthusiastic, at 4.27, good for 77th in baseball.
The disparity between performance and results continued in Oswalts’ start yesterday. While his fastball barely topped 90 MPH, Oswalt worked around three first-inning runs, shutting the Cubs out in the subsequent six innings. Between the second and fifth innings, Oswalt did not strike out a batter, adding to the concern. In the final two innings, Oswalt got four of his six outs on strikeouts, but that is hardly sustainable and nor does it make up for the overall lack of strikeouts over the past six weeks.
Oswalt needed time to deal with back problems in late April and throughout the second-half of the 2009 season as well. It is possible that his back is still bothering him, and it could be causing him to overcompensate in other areas. It could be a completely new injury, or the return of another chronic injury. Whatever the case, the continued use of Oswalt puts him at a much higher risk of serious injury.
It is in the team’s best interest to give Oswalt some time off. That would mean Kyle Kendrick stays in the rotation and Vance Worley returns, but the Phillies cannot afford to lose Oswalt to a serious injury later in the season when he could be a vital key to post-season berth. Should the Phillies reach the promised land, Oswalt would give the Phillies additional firepower in the playoffs.