One of the forefront questions for the Rays to answer before next season is Davis' role. After two mediocre years in the Rays' rotation, a plethora of starters forced the Rays to move Wade Davis into the bullpen, a move that he publicly opposed but finally accepted. It is not easy for a former top prospect to be forced to the bullpen after only two years to prove himself in the rotation.
With Wade Davis anchoring the pen and improving his velocity as the season progressed, the move to the bullpen can be considered a success. Davis ditched his slider and changeup, re-discovered his curveball, used his cutter more frequently, and amped up his fastball velocity. All of these changes can be credited for Davis' fine season. Whether or not he can keep up the velocity and survive with only three (but good) pitches in the rotation is debatable.
The most important pitch in Davis' arsenal is his fastball. While he used to throw it in the mid-90s in the minors, his fastball velocity was in the low 90s for much of 2010-2011. The combination of a lack of velocity, no great movement, and no real changeup to keep hitters honest made the fastball very hittable.
Converting Davis to the pen was supposed to allow him to throw much harder, which he did. Wade's fastball velocity averaged 94.45 (according to brooks baseball) during his 2012 campaign.
Now the two key questions facing the Rays are (1) at what velocity does Davis need to work at with his fastball to be successful and (2) can Davis throw that hard as a starter?
To find the answer to the first question, I took a look at how successful Davis' fastball was during the 2012 season depending on the velocity. Since Davis most likely will work with only three pitches in the rotation (fastball, cutter/slider, and curveball), we don't have to account for changes in his arsenal. For example, assuming Davis doesn't add a changeup to his repertoire, there is no need to consider whether or not a hitter will take a different approach to his fastball. The batters will still be facing fastballs, cutters, and curveballs. The only difference, presumably, will be the velocity.
The blue line is whiffs per swing (percentage). The green line is whiffs per pitch. The red line is the percentage of balls put in play out of the amount swung at. Please note that the "89 and below" sample size is very small and should be taken with a grain of salt. Some changeups/cutters may have been incorrectly classified as fastballs, since I doubt he threw any 86 mph fastballs.
As one would expect, Davis is much more effective when working in the mid-90s than in the low-90s. What needs to be determined is the velocity that he needs to sit at for him to have success in the rotation.
The average whiff per swing rate in baseball among starting pitchers in 2012 was around 14 percent. Some pitchers with elite fastballs managed to get that rate north of 20 percent.
As the chart shows, Davis sits north of the 14% mark (on average) on all fastballs 92 mph or higher. So if Davis is able to sit in the 92-94 range with the ability to reach back for 96-97, then we are talking about him getting a well above average whiff rate on the fastball, which is key to his success.
Consider this: If Davis throw 30% of his fastballs at 92 mph, 30% at 93 mph, 30% at 94 mph, and 10% in the 94-96 range, his fastball will average 93.3 mph and his whiff rate (based on the numbers compiled in 2012) will be 23.65 percent.
Now I would take this conclusion cautiously and not claim that it is the absolute truth. The best idea is the heavily scale back the numbers. I certainly do not believe that Davis will get more whiffs on his fastball than David Price. But the numbers themselves, even if reduced, still strongly suggest that, based on the way Davis threw his fastball in 2012 (it can include his mentality, the other pitches, his arm slot, etc...), his fastball, even at a lower velocity, should be a very effective pitch. Whatever the reason or cause behind the pitch's new found success is debatable. I just do not prescribe to the theory that Davis finally had success with his fastball only because he was airing it out in short appearances. His success, even in the 92-93 range, suggests that Davis showed an improved ability to generate swings and misses with his fastball even at lower velocities.
Now that it is clear where Davis' velocity needs to be at (92-94 and able to touch 96), the question has to be asked: can Wade Davis throw that hard as a starter?
In 2010, Davis averaged 92.5 mph with his fastball. In 2011, the numbers dropped to 91.8. 2010's velocity numbers are not far off the goal, so 93.3 certainly seems reasonable. Davis also showed the ability to max out at 97 mph, which is very important in putting hitters away.
As recently as the latter part of the 2011 season, Davis showed he can get his fastball into the targeted range. After starting the year off throwing in the 88-90 range with poor results, Davis began throwing in the steady low-90s. Late in the year, Maddon urged Davis to come out throwing harder, and the results were obvious. In August and September, Davis' fastball averaged over 93 mph.
Unfortunately, the results never came with the velocity spike. Most of this is probably due to Davis' weak arsenal, as he was still using his slider, a poor curve, and a horrific changeup. Another factor could be his mentality out of the rotation.
I am a firm believer that if Davis moves back to the rotation, he can be a middle of the rotation starter, if not better. His cutter can be devastating, his curveball returned to form this year, and his fastball in the 93 range should be effective. The experience of being the bullpen, in my opinion, should be a positive for Wade. He learned to control and refine his arsenal and how to aggressively attack hitters, something we haven't seen from Davis since his fabulous debut in 2009.