Wade Davis: Middling Starter, Star Reliever

It's no secret that pitchers who move from the starting rotation to the bullpen perform better. No longer worried about conserving energy or playing a cat-and-mouse game with hitters multiple times, starters-turned-relievers ramp up the velocity -- and the strikeouts. But even by those standards Wade Davis' transition during the 2012 season was shocking. Davis, who had a mediocre 92 ERA+ and 6.7 strikeouts per nine innings as a starter from 2009-2011, improved to the tune of a 157 ERA+ 11.1 K/9 out of the 'pen in 2012.

We'll soon find out whether Davis can retain some of those gains in as a starter in Kansas City, as the 27-year-old righty acquired in the James Shields-Wil Myers megadeal will return to the rotation in 2013. Unless he can ramp up the radar gun readings while going six innings, the answer might be "no." 

Davis didn't add a new pitch to his repertoire last year, throwing his fastball about two-thirds of the time, mixing in curveballs (20%) and sliders (10%) and throwing a changeup monthly. He didn't fine-tune his control, either, walking more batters (3.7 per nine) than he did as a starter (3.2). Rather, he boosted the velocity of all his pitches in a big way, leading to a major uptick in whiffs.

Here's Davis' velocity and miss rate with his pitches as a starter, compared to the average for right-handers:

Davis as a starter

	Davis as a SP		MLB Avg. for RH SP
Pitch	Velocity	Miss Pct.	Velocity	Miss Pct.
Fastball	91.8	14.1	91.5	14.1
Slider	85.6	25.2	83.9	29.6
Curveball	78.8	15.4	76.9	28.3

As a starter, Davis had a league-average fastball both in terms of velocity and miss rate. He threw his slider and curve hard, but his miss rates were paltry. In relief, Davis gained a couple of ticks on all of his pitches and posted elite miss rates:

Davis as a reliever

	Davis as a RP		MLB Avg. for RH RP
Pitch	Velocity	Miss Pct.	Velocity	Miss Pct.
Fastball	93.4	26.8	92.9	18.2
Slider	89	41.4	84.1	33.5
Curveball	81.1	31.5	78.4	31.6

A couple extra ticks of velocity makes a major difference, particularly with fastballs. Righty pitchers throwing 91-92 MPH fastballs surrendered a .465 opponent slugging percentage last season, over 40 points higher than pitchers sitting between 93-94 MPH (.424). Davis also dropped his fastball slugging percentage about 40 points while moving from that 91-92 range as a starter (.439) to 93-94 in relief (.398). Short of keeping the extra velocity while getting stretched out, Davis could return to mediocrity as a starter.