Blue Jays: Ranking the top 10 relief pitchers in the AL East in 2023

6: Kenley Jansen, Boston Red Sox

The Red Sox needed to invest in their bullpen after a rough 2022, particularly the closer role. So how did they go about doing that? They signed one of the greatest closers in MLB history. After a one-year stint in Atlanta, Dodgers great Kenley Jansen signed a two-year deal with the Red Sox. While some of the guys on the list so far have only had brief Major League success, Jansen is the exact opposite. In his 13-year career, he has 391 saves (eighth all time), a 2.46 ERA in 769 innings pitched (third among relievers with at least 750 innings), two NL reliever of the year awards, a fifth-place Cy Young finish, and countless other accolades. The point is that Jansen is one of the best to ever do it, and is a huge pickup for the Red Sox. Having heard all that though, you might be wondering why he isn't ranked higher, here's why.

While his 2022 would have been a great season for most relievers, it was one of the worst of Jansen's career, as he posted a 3.38 ERA in 64 innings with the Braves, despite leading the league in saves with 41. In fact, he's been on a bit of a decline over the past five seasons. Through his first eight seasons, Jansen had a 2.08 ERA in 477 innings, but since then, he has a 3.08 over 292. This has coincided with less usage of his cutter, which used to be so dominant, that at his peak made him essentially a one-pitch pitcher. Recently, he's begun using this pitch about 60% of the time and has mixed in his fastball and slider more often. Despite all this, his advanced metrics were actually really good in 2022, sitting near the top of the league for xERA, xBA, xSLUG, and strikeout rate, with solid numbers in the other areas.

The main reason for concern with Jansen is that while lots of other guys on this list seem to be entering their prime, he seems to be exiting his. While a lot of the underlying numbers suggest that he probably pitched better than a 3.38 ERA last year, this is a division loaded with reliever talent, and he'll have some tough competition. Who knows, maybe this ranking will look silly a few months from now, but the guys ahead of him are just too good to have him any higher.