The Boston Red Sox bullpen is the clear weakness on the team. Last night, the unit blew a 6-1 lead and, in the process, blew their 15th save of the season. Only the New York Mets have more blown saves than the Red Sox, and some are looking to Pawtucket Red Sox reliever Trevor Kelley as a potential savior. Kelley currently owns a 1.04 ERA in 34.2 minor league innings, but his underlying numbers suggest he cannot maintain his success at the major or minor league level.
Trevor Kelley Not Boston Red Sox Bullpen Fix
On the surface, Trevor Kelly is having a great season in Pawtucket. Through 34.2 innings, the righty has posted an impeccable 1.04 ERA. Preventing runs is the ultimate point of pitching, so Kelly has performed well when on the mound.
That said, the underlying numbers suggest Kelly has gotten ridiculously lucky thus far in the season. As of this posting, Kelly has a 3.94 FIP and a 6.11 xFIP. For those who aren’t familiar with Fangraphs’ advanced statistics, FIP (Fielding Independent Pitching) is basically ERA without batted ball luck. xFIP, meanwhile, is FIP but with a league-average home run rate. His 3.94 FIP suggests that Kelley should be a below-average minor league arm, while his 6.11 xFIP suggests he should be giving up significantly more home runs than he is.
FIP and xFIP aren’t perfect, and some pitchers are capable of consistently outperforming their underlying numbers. Throughout his minor league career, Kelley has pitched 216.1 innings to the tune of a 2.33 ERA and a 3.17 FIP. This shows that Kelley has managed to outpitch his peripherals, but not on this ridiculous level. Additionally, Kelley has always managed to minimize home runs. According to Fangraphs, Henry’s current 0.52 HR/9 is actually the highest of his career. However, he only has a 30.9% ground ball rate, so there’s a very real possibility that he starts giving up more home runs when he faces major league talent, especially within the batter-friendly confines of Fenway Park.
Kelley’s Pitch Tool
In addition to underwhelming peripherals, Trevor Kelley doesn’t have the most impressive pitch tool. According to Sox Prospects, Kelley is a two-pitch guy with a high-80’s fastball and a mid-70’s slider. The fastball obviously doesn’t have ideal velocity but it does have a little sink. The slider, meanwhile, has decent horizontal movement but doesn’t have any vertical break. Overall, it’s a fairly unremarkable pitch tool.
Kelley is a sidearm thrower, and his unique mechanics makes it hard for right-handed batters to pick up the ball. Lefties, however, have no such issues and won’t struggle to make consistent contact. Due to his subpar pitch tool, Kelly is limited to a righty-only specialist role. In today’s MLB, bullpens are asked to do more and more and go deeper and deeper into games. Even if Kelley can consistently outpitch his peripherals, there isn’t much room for platoon relievers anymore.
Sox Prospects projects Kelley as “a minor league relief arm”, and that’s exactly what he is. The Red Sox could promote him and hope that he outperforms guys like Ryan Weber and Josh Smith. However, don’t expect Kelley to come in and have a Ty Buttrey level impact on the 2019 Boston Red Sox.