If you’re noticing a trend in these picks, most of the players have been a disappointment so far in their Red Sox careers. Part of a deal with the St. Louis Cardinals, Kelly was acquired with Allen Craig for John Lackey. As a starting pitcher, he’s been nothing but mediocre over his career, with a 4.13 ERA in 431.1 innings pitched. Red Sox management figured that out part way through last season and moved Kelly into a full-time bullpen role.
Since making the transition, he put up a 1.02 ERA with 10.9 K/9 in 14 relief appearances. With a high-90s fastball and devastating slider that he developed in the postseason, Kelly has all the tools to develop into a shutdown middle innings reliever. But just 14 regular season appearances is an incredibly small sample size. All told, he faced just 80 batters as a reliever including the postseason in 2016. It’s hard to extrapolate just how productive he’ll be in 2017, but it’s clear that he belongs in the bullpen.
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Thornburg and Kimbrel will get all of the attention at the back of the bullpen this season, but Joe Kelly, along with the aforementioned Carson Smith are prime candidates to fly under the radar with great seasons.