The Yankees bullpen proved to be one of the teams biggest strengths this past season. While some feared a drop off in ability with the loss of David Robertson in free agency, new Yankees closer Andrew Miller and homegrown flamethrower Dellin Betances anchored the back of the one of the best bullpens in baseball. Together with Adam Warren and Justin Wilson, the pen helped the Yankees reach the postseason for the first time since 2012. Even after such a stellar year, though, are there still some potential red flags for next year's relief corps?
One possible problem is the top-heavy nature of the bullpen. Miller and Betances may have been two of the best relievers in the league, but they're only two guys. Along with Wilson, they threw nearly 40% of the Yankees relief innings this year, and even then, Betances started looking worn down at the end of the season. While Warren provides some depth, he's almost bound to be put into the rotation at some point next year, meaning the pen is down to three dependable arms, and a huge amount of question marks. Fans saw just how taxing having a shallow pen can be on its main cogs, as Chasen Shreve and to a lesser degree Betances struggled down the stretch this season, and if Shreve can't find his grove again next year, the pen will be even more shallow. A lack of depth in the bullpen is a problem many teams have, but it's still a reason why next year's bullpen could be in some trouble.
Also worrisome are the late season struggles of the bullpen. Overall, in the first half of the season, the Yankees had the most valuable group of relievers in the league according to fWAR. In the second half, however, they dropped to 11th. Their walks increased, opposing hitters average against jumped nearly 40 points, and their collective WHIP in the second half ranked among the worst in baseball. Again, some of this probably resulted from some wear and tear on the bullpen, but it's possible it could signal that the Yankees pen - while good - may not be as elite as it appeared early in 2015.
The late season struggles of Betances and Shreve are particularly worrying. Betances struggled with his control during the second half, looking wild en route to posting a 5.11 BB/9 since the break. While he managed to keep his ERA down, if this signals future control issues, it will come back to bite him at some point. Betances' fastball, in many ways, led to his issues late in the year, as hitters started jumping on it and laying off his curveball. In the second half, hitters managed far fewer whiffs per swing against his fastball, and correspondingly, their line drives per ball in play jumped significantly. His fastball location probably helped lead to this, as he left more fastballs up in the middle of the plate late in the year than he did early on:
Shreve became a key member of the Yankee bullpen early on, only to fall off a cliff towards the end of the year. In the second half of the season, Shreve posted a 4.76 ERA, 7.41 FIP, and walked nearly eight batters per nine innings. Over just 22.2 innings after the All Star Break, he accumulated -0.7 fWAR. His decline seriously thinned out the Yankee bullpen - they'll need him to at least regain something close to his dependable form next year for the bullpen to reach its potential.
The Yankees have recently been quite good at developing young relievers, but that did not really happen in 2015. Jason went into lots of detail on the subject here; the team did not get nearly as much as hoped for out of the likes of Nick Rumbelow, Nick Goody, Bryan Mitchell, and Jacob Lindgren, among others. Some of it was due to injuries, but a lot of it just amounted to ineffectiveness. With few promising performances out of this bunch, will the Yankees have the arms they'll need to build some valuable, effective depth in next year's bullpen?
In all likelihood, the Yankees' bullpen will be one of the better groups in the majors in 2015. The back end of Miller/Betances is one of the best duos in the majors, and Warren and Wilson have shown themselves to be quite good. It helps that Joe Girardi is one of the best in the majors at using his bullpen as well. However, with the concerns about the offense taking a step back next year, plus a rotation that has struggled to stay healthy in recent years, the Yankees will probably need an elite bullpen to reach the playoffs again. Right now, there's certainly reason to wonder if their current crop of relievers are up to the task.