As we all know by this point, Andrew Miller was a classic Theo Epstein high-risk, high-reward signing. The former first round pick seemed like an almost sure-thing while in the Tigers farm system, with the entire baseball world expecting him to be a top-of-the-rotation starter by the time he reached his prime. Obviously, things didn’t work out like that, possibly because Detroit rushed him to the bigs too soon. Now, in his age-27 season, it seems the lefty has found a niche with the Red Sox, who were bold enough to take a chance on the former phenom prior to last season.
This 2012 season has been the first season in which Miller has been used solely as a relief pitcher since 2006, his first year in the majors. The move has allowed Miller to make some adjustments which are better suited for his game, and has especially cut down on the control issues that have plagued him throughout his career. In 23 appearances for the Sox this year, he has a highly impressive 1.89 ERA, and an equally impressive 2.58 FIP that suggests there shouldn’t be too much regression in his future. He’s done an impressive job in keeping the ball in the park, averaging just 0.47 HR/9 innings. He has gotten a bit of help from a below-average 6.3% HR/FB ratio, but he’s been superb nonetheless.
The most noticeable change in Miller’s game has been his ability to work the strike zone and keep hitters off balance. He is averaging a career-high 9.5 K/9, while also allowing a career-low 2.8 BB/9. He has done this with a better command of the zone combined with improved stuff. Miller has hit the strike zone 47% of the time this season, per Fangraphs, which is an improvement over each of the past two horrible seasons. Even with an improved Zone-rate, opposing batters are making contact significantly less often than they have in the past. Opponents’ 67% contact-rate in 2012 is about 15 points higher than his career average, and he’s never had a season with that number finishing under 80%. Surprisingly, the percentage of at bats he starts of with a strike (53.5%) is not much higher than his career average, and is four points lower than it was last season. With his improved peripherals, I was expecting to see a higher-than-normal rate for him.
With the move to the bullpen, we have also seen a shift in Miller’s repertoire. As a starter, he worked a changeup into his arsenal to go with his fastball, sinker and curveball*. However, with a smaller number of hitters to face, he has scratched the changeup and gone with a fastball, sinker, curve attack. The results have been overwhelmingly positive, as he is inducing a 13.8% swinging-strike rate. According to the Fangraphs leaderboards, the league average SwStr% for relief pitchers this season is 9.8%. The shift to the bullpen has allowed Miller to induce more whiffs by allowing him to exert more energy pitch-to-pitch. While he has typically thrown his fastball around 92MPH in years prior, he is averaging a little over 95MPH on his heater this season. That same trend in increased velocity can be found in his other pitches as well.
Finally, Miller has been able to find success by facing primarily left-handed batters. The southpaw has always (unsurprisingly) pitched better against like-handed hitters, but as a starter the manager can’t pick and choose your matchups. This season, he has faced almost double the amount of lefties compared to righties, and the results have been positive. The biggest advantage he has had against lefties has been that ability to control the strike zone, as his BB% nearly quadruples against righties. While he isn’t pitching poorly to anyone, no matter their handedness, there’s a clear improvement against lefties. He has allowed them to hit a .190 wOBA this year, while righties have a .281 wOBA.
There is likely some regression on the horizon for Miller, who is currently sporting a nifty .227 BABIP and 83.3% left-on-base rate. However, the move to the bullpen was a tremendous decision by the Red Sox brass, who could have easily pushed Miller aside and moved on without him this season. With Rich Hill hurt and Franklin Morales in the bullpen, Miller has been a key cog as a left-handed reliever. Even with Daniel Bard and Andrew Bailey returning to this team at some point, along with Hill, it seems Miller has solidified a spot in this team’s bullpen.
* All pitch-type classifications were obtained from Brooks Baseball’s Pitch F/X tool.