Kenley Jansen signing fortifies a vastly improved Red Sox bullpen

ATLANTA, GA - OCTOBER 01: Kenley Jansen #74 of the Atlanta Braves celebrates the 4-2 victory over the New York Mets at Truist Park on October 1, 2022 in Atlanta, Georgia. (Photo by Todd Kirkland/Getty Images)
ATLANTA, GA - OCTOBER 01: Kenley Jansen #74 of the Atlanta Braves celebrates the 4-2 victory over the New York Mets at Truist Park on October 1, 2022 in Atlanta, Georgia. (Photo by Todd Kirkland/Getty Images) /

The Red Sox bullpen receives a major upgrade with Kenley Jansen

The Boston Red Sox placed an emphasis on improving their bullpen this offseason, and on Wednesday, they proved they were serious about accomplishing that goal when they agreed to terms with Kenley Jansen on a two-year, $32 million contract.

Boston’s bullpen posted a 4.59 ERA and they were charged with 28 blown saves last season; both numbers tied for the fifth-worst in the majors. They also tied for third-worst in the majors with 101 meltdown performances, a FanGraphs metric that uses Wins Probability Added to measure a reliever’s impact.

The Sox struggled to find a permanent option to fill the closer role last season, cycling through various options who never panned out due to inconsistency, injury, or just plain inability. Without a reliable closer to protect the ninth inning, Boston’s bullpen lacked structure, preventing their relievers from having the stability that comes from a defined role.

Adding Jansen changes everything.

The right-hander produced a 3.38 ERA, 1.047 WHIP, and 12.0 K/9 in 64 innings for the Atlanta Braves while leading the National League with 41 saves. By comparison, the entire Sox bullpen compiled 39 saves, ranked 18th in the majors. They had 33 losses charged to a reliever, tied for the 8th-most in the majors. Jansen hasn’t been tagged with that many losses over the course of his 13-year career.

Jansen established himself as one of the best closers in baseball throughout a 13-year career spent mostly with the Los Angeles Dodgers (2022 was his first season elsewhere). His 391 career saves rank eighth in major league history, he leads the majors with 329 saves since 2014, and with 90 saves over the last three seasons.

Age is beginning to creep up on the 35-year-old but a two-year commitment mitigates any risk for a pitcher who has proven to be among the most effective closers in the game. Jansen has been a workhorse, logging 60+ innings in nine of the last 11 seasons, with one of the exceptions being the shortened 2020 season. That type of durability is appealing for a Red Sox pitching staff that was ravaged by injuries last year.

Jansen’s Statcast data remains strong, ranking in the 80th percentile in Average Exit Velocity, 88th percentile in Hard Hit% and 93rd percentile in K% last season. He was in the 93rd percentile in xSLG, 97th in xERA/xwOBA and 98th in xBA, per Baseball Savant.

His declining fastball velocity, which now ranks in only the 36th percentile, was a concern that led some to believe that the three-time All-Star was beginning to fade. Jansen doesn’t throw as hard as he once did but this is primarily a product of a change to his approach. He abandoned his mid-90’s four-seam fastball a few years ago. Jansen is now a sinker/cutter/slider pitcher, an arsenal that doesn’t rely on high velocity.

His cutter has been particularly dominant, holding opposing hitters to a .170 batting average and .262 SLG while generating a 28.2 Whiff% last season.

Jansen remains an elite strikeout artist even without the high heat, ranking in the top seven percent of the league with a 32.7 K% last season. His walk rate has been drifting in the wrong direction since altering his approach to remove the four-seamer from his arsenal but aside from a brief hiccup in 2021 when his 12.9 BB% placed him in the bottom eight percent of the league, Jansen has been about average in that department over that last few years. He recovered last season with an 8.5 BB% that ranked 85th out of 152 qualified relievers.

Chaim Bloom has given the Red Sox bullpen a drastic makeover that has transformed a clear weakness into a potential strength. There’s no longer a question of who will be getting the ball in the ninth inning for a save situation. With Jansen locking down the end of games, the rest of the bullpen can fall into established roles.

Boston has also added Chris Martin and Joely Rodriguez to a bullpen that still includes John Schreiber and Tanner Houck, creating enviable depth. We can potentially add Garrett Whitlock to the mix, depending on how the Red Sox address the holes in their starting rotation, which would provide them with another dominant weapon to deploy in a versatile role, giving Boston one of the deepest bullpens in the game.

Manager Alex Cora shouldn’t need to worry about burning out his best relievers due to a lack of trustworthy options. Spreading the workload to an expanded circle of trust will keep Boston’s best bullpen arms fresh over the course of a long season.

The Red Sox still have a lot of work to do in order to consider this offseason a success, but making a splash with a big name to fill a position they desperately needed to upgrade is an excellent start. Considering how much Boston struggled to protect leads last season, adding a legitimate closer is arguably the best move the Red Sox could make, with the exception of re-signing a certain shortstop. Unfortunately, that ship has sailed, and the Sox now have more work to do to save this offseason than they did before getting Jansen.