Welcome to BP Boston’s new Roster Recap series! Over the next four months, we’ll be breaking down every player on Boston’s 40-man roster and many of their top prospects in order to provide a comprehensive overview of the Red Sox roster’s strengths and weaknesses, as well as what we can expect moving forward. There’s no better time than the offseason to review the best (there was some best!) and worst (there was a lot of worst!) of the past year in red and navy. You can see previous editions of Roster Recap here.

The Red Sox entered last season with three lefties in line for the major league bullpen, and PECOTA was not very impressed with any of them. Robbie Ross was pegged for a 0.2 WARP season and Craig Breslow was projected to contribute at a replacement level 0.0 WARP. Tommy Layne, with a recent if small history of success, seemed dragged down by iffy peripherals, and was given a -0.2 WARP projection. As I wrote in April, Layne had been dominant against lefties in particular, making him a promising part of the bullpen as a lefty matchups man. As I found out the afternoon that piece was posted, that didn’t mean Layne was a lock to actually stay in the majors all season.

Layne made his way back to the major league roster by the end of that month, excelling in May (1.64 ERA in 11 innings) and sticking with the club for the rest of the year. Used as a true matchups man, he found success in that role; to the extent that a late-blooming journeyman LOOGY can be a bright spot of the bullpen moving forward, that’s what he appears to be.

What Went Right

Layne’s success starts and ends with the 102 plate appearances he tallied against left-handed hitters. The .248 OBP they managed against him was more “very good” than “outstanding,” but while pitching around the zone meant a predictably high walk rate (more on that later), that approach also had the desired effect: lefties slugged just .170 against Layne, and none of those 102 batters managed to hit a long ball.

Against lefties, Layne fared exactly as well as Dallas Keuchel and Wade Davis. We’ll take that.

Last year, a low slugging mark helped keep Layne’s TAv down to just .136 against lefty hitters; of sixty-three lefty relievers who pitched in at least 30 games in 2014, only Sean Doolittle had a better mark (.097 TAv against lefties). Even in his most wintry of Winter Soldier relief seasons, Zach Britton (.139 TAv) didn’t do better than Layne. Aroldis Chapman (.151 TAv) didn’t do better than Layne.

Still, Layne’s brief but dominant 2014 LOOGY experience seemed to offer little beyond confirmation that Layne threw with his left arm and could have success in that role — not that he would. If the Doolittle-Britton-Chapman company was the kind that Layne needed to keep in order to call his 2015 season a success, the odds seemed heavily stacked against him. And yet…

Layne ended the 2015 season with a .172 TAv against lefties, behind only a who’s who of baseball’s top pitchers who faced lefties for at least 50 PA. He ranked behind only Javier Lopez, Britton, Mark Melancon, Carter Capps, Brandon Maurer and Dellin Betances among relief pitchers. Against lefties, Layne fared exactly as well as Dallas Keuchel and Wade Davis. We’ll take that, even if it’s hard to explain how he did it. When the pressure was on, Layne was only counted on when he was in a position to succeed; according to Baseball Reference, Layne held batters to a .436 OPS in High Leverage situations.

What Went Wrong

No baseball player gets the platoon advantage 100% of the time, and in Layne’s case, he still ended up facing more RHH (105) than LHH (102). Even though his splits were so extreme that on paper, he looks like he was out there for RHH (21 innings) quite a bit less than LHH (26.2 innings). Just as Layne tended to pitch in high leverage situations when he’d be able to face a lefty, he sputtered when used less strategically: a .713 OPS for batters in Medium Leverage situations, and a bloated .795 OPS in Low Leverage.

Layne was no Keuchel against righties, who managed a .310 TAv against him. If you’re going to hack it as a matchups reliever, it makes sense to judge you based on how well you perform in the intended matchups. Still, it’s not like the other innings don’t count. Layne yielded a 26.5% LD% against righties, a not-insignificant sign that they had a pretty easy time squaring him up. A .517 slugging percentage allowed against them tells the same story.

Between Layne’s poor results against RHH on batted balls and very good results against LHH, you can’t really blame him for closing his eyes and wishing as hard as he could that he could just kind of skip RHH. Since he had a little more control over those situations than wishes, the fact that he did skip more than a few RHH is probably not a question of command. Layne’s 6.86 BB/9 against RHH is understandable, but no less horrendous than it sounds. That walk rate is tantamount to an admission that Layne has little business pitching to major league RHH. Layne’s performance against RHH in 21 innings was enough to raise the entire team’s ERA from 4.30 to 4.34.

Outlook for 2016

To the extent Layne finds success, it’s probably always going to feel fluky; that’s the nature of cutting up a reliever’s small sample of innings into even smaller pieces. But there is hope. In the calculation of WARP that depends on FAIR_RA, Layne was barely helpful in 2015: a 0.2 WARP. In the newer calculation of WARP that depends on DRA and more variables we’ve come to trust, Layne’s WARP skyrockets to 0.7, a strong figure for a pitcher with an innings total under 50. Not all walks are made equal; if you’re walking the right batters on purpose, maybe it’s not luck when you then seem to get more than your fair share of ERA credit.

Despite its overall lack of success, the Red Sox rotation did surprisingly well in 2015 in terms of pitching deep in games, ranking 11th in baseball with an average of 5.85 innings per start. If the Red Sox can maintain or even improve that figure, they won’t be tempted to lean on Layne for several batters at a time the way they did last April. And the more Layne pitches to his strength, the better off he’ll be.

Photo by Dan Hamilton/USA Today Sports Images