After posting a 2.43 ERA and 2.73 FIP in 33.1 innings out of the bullpen last year, it seemed as if former top prospect Scott Elbert had found his future in the bullpen. This year though, he has struggled, posting a 5.87 ERA and a 6.35 FIP.
So what’s wrong? His slider, apparently.
“I feel good,” Elbert said. “I’m pounding the zone, getting ahead and the next thing I know, they’re on base. I’m not putting away hitters like I should. Last year, they would swing and miss the slider. This year, it seems like it’s in play every time.”
Last year, batters swung at 150 sliders thrown by Elbert. They fouled off 28.7%, missed on 36.7%, and put the ball in play 34.7% of the time. This year, batters have swung at 31 pitches. The results are 25.8% fouls, 41.9% misses, and 32.3% balls in play.
So the batters aren’t actually swinging at missing at the slider with less frequency. However, there are problems.
1) He can’t throw the slider for strikes. It’s been thrown for a ball 40.3% of the time this year compared to 27.2% of the time last year.
2) When the slider does get hit, it has hurt. Home runs have been a reason for Elbert’s struggles, as he’s already given up more homers this year (2) than last year (1), and both of them have come on sliders.
3) He can’t put batters away with the slider in two strike counts. They’re swinging and missing at 14.8% of two strike sliders this year compared to 24.3% last year.
A reason for all three? Could be the speed differential between his fastball and slider.
“I don’t think there’s enough speed differential between my fastball and slider,” said Elbert, who allowed all three batters he faced to reach base on Friday and was charged with the decisive run in the Dodgers’ 5-4 loss to the Cubs.
In 2011, his fastball clocked in at an average of 92.4, while his slider came in at 87.9. A difference of 4.5. In 2012, his fastball has averaged 92.0 and his slider at 88.9. A difference of 3.1.
So indeed, the differential is 1.4 mph less this year than last. Not seemingly a significant amount, but it’s quite a bit in baseball terms.
The speed differential between the slider and the fastball is important because it’s much easier to time a pitcher if the hitter just has to sit on one velocity range. The more often the batter is on time, the less often he’ll swing and miss, because even if the movement is different, his hands will be back more often than not, especially with two strikes and a more defensive approach.
Whether the change in differential is actually the reason for Elbert’s struggles is debatable, but it is clearly actually happening and it wouldn’t be unreasonable to suggest that it plays a role in his 2012 performance to date.