Much has been written this offseason about the wealth of bullpen depth it appears the Red Sox have heading into the 2014 season, and for good reason. With additions like Burke Badenhop and Edward Mujica, Ben Cherington has done a great job strengthening that unit. This is a big step forward from the end of last season, when the team leaned heavily upon the shoulders of Koji Uehara, Craig Breslow, and Junichi Tazawa, along with rookies Brandon Workman and Drake Britton. Injuries were a major factor for how thin the group was by the end of the season, and the most notable of those injuries were to Andrew Bailey and Joel Hanrahan, both of whom were supposed to be the late-inning anchors for the entirety of 2013. In addition to those two, though, the Red Sox also felt the absence of Andrew Miller, who was quietly outstanding in his half of season work last year. With a new season upon us, this could be the year in which the big lefty breaks out as a consistent contributor on this team.
Miller famously failed when he first reached the majors as a top prospect, one who many hoped would be a front-line starter for years to come. Then in 2012, the Red Sox decided to shift him to relief duty on a full-time basis, and the move has paid off big time. He has made 90 appearances in the past two seasons -- second most for the team in that span behind Tazawa -- and has completely turned his career around. In those 90 appearances, he has a 138 ERA+ over 71 innings, along with a 99/37 K/BB. The walks have still been a bit of a problem for the 28-year-old, but that's a problem that is more easily hidden in the bullpen, especially when you strike out batters as often as Miller does.
Photo Courtesy of Jared Wickerham
His strikeout numbers are really his true bread and butter, and are the major reason he could be looking at a big breakout this season. He's always had high-quality stuff, but he was never able to harness it in a starting role, putting up mostly average strikeout numbers in his years in the rotation. Since shifting to the bullpen, though, he's been able to let loose a little more, racking up strikeouts at an impressive rate. Over the last two years, he has struck out 12.5 batters per nine innings, and a total of 32.5 percent of the batters he has faced. The numbers were especially impressive last season, when he had 14.2 K/9, and a 35.6 percent K-rate before being shelved for the season in June after 30-2/3 innings of work. To put those numbers into context, that K-rate was the seventh best in all of baseball among relievers with at least 20 innings in 2013, while his K/9 ranked second, trailing only Aroldis Chapman. If he can continue that upward trend this season, he could reach Kimbrel-esque strikeout totals.
Fortunately for the Red Sox, all signs point to Miller adapting much more to his relief role last season. His stuff was incredible, carrying a swinging strike rate of 13.2 percent, about 3.5 points higher than his previous career high. Along with that, he threw his first pitch for a strike more often than he ever has before, hit the zone at a career-best rate, and induced swings both in and out of the zone better than ever. Since he got injured so suddenly and had to miss half the season, it's tough to decipher what is small sample noise and what's real. Using the eye test, it seemed mostly real, as he was a dominant force for the first few months of the year. Combining the eye test with the realization that he's finally getting comfortable in a new role, there's plenty of reason to believe those strides he took are here to stay.
In addition to all of this, Miller may also see his share of time in high-leverage situations. As of right now, he likely finds himself behind Uehara, Tazawa, Breslow and Mujica on the depth chart, but bullpens are so fluid and unpredictable that much of that could change even by Opening Day. It's also important to consider that Miller was used in big spots last year, thanks to his ability to strike batters out. Farrell has indicated he wouldn't be afraid to turn to him in the ninth inning if Uehara can't go. Though he's a lefty, he doesn't show the typical splits of a southpaw, and could succeed in a late-inning role regardless of the handedness of the batter. Last season, he actually showed reverse splits, with opposing lefties posting a .324 wOBA, while opposing righties put up a .263 mark. For his career, his righty/lefty wOBA split sits at .363/.333.
Since he wasn't an offseason acquisition, and he didn't play a role in the late-season run the Red Sox made to the championship, it's easy for Andrew Miller to become something of a forgotten man. Once you remember how dominant he was for the first half of 2013, it's easy to start to get excited about what this year could possibly bring for the big lefty. Given his high strikeout totals and upward trending numbers around the strikezone, there are plenty of reasons to believe that this is the season that Andrew Miller makes his name as one of the better relief pitchers in the American League.