AnalysisNL West

In Defense of Kenley Jansen

If you spend some time on Dodger Twitter, you’ll quickly realize that no other player on the 26 man roster draws more ire from the fanbase than Kenley Jansen. Every blown save is a cause to find a new closer, and if you disagree then you will quickly be attacked by the fanbase for taking up such an indefensible position. Somehow, through all of this fan outrage, Jansen has continued to hold onto his closer job despite being second in the league in blown saves since 2018. Both Dave Roberts and Andrew Friedman know that Kenley Jansen is still an elite reliever. Why is that?

Before the 2020 season, Jansen went to Driveline to find out why he just had the worst season of his career. In the 2020 season Jansen converted 85% of his save opportunities. While that mark is the third worst in his career, the underlying metrics tell a different story. According to Baseball Savant, Kenley Jansen ranked in the top 10% of all pitchers in 2020 in average exit velocity, expected ERA, hard hit percentage, chase rate, expected weighted on base percentage, and expected slugging. All this suggests that hitters really struggled to deal with Jansen’s cutter in 2020 and perhaps more importantly, that Jansen was the victim of particularly bad batted ball luck. The Statcast data from perhaps his most infamous blow of the season, September 12 against the Astros, supports this as well.  He only allowed three hard hit balls that night, and those balls had the lowest, second lowest, and fourth lowest expected batting averages of any balls in play during that outing. Meanwhile, the other four balls in play had an average exit velocity of 84.2 mph, the average exit velocity in 2020 was 89 mph. Those balls had an 87.5% chance of falling for a hit. Going back and rewatching the top of the ninth confirms that these balls were dumped all over the field with very little chance of a defender making a play. Meanwhile, Jansen doubled his season whiff rate on his cutter, as Astros hitters swung and missed at 56% of cutters thrown that night.  Everything from the batted ball data to the whiff percentage on his cutter, indicated that this should’ve been a dominant outing from Jansen. Instead this ended up being perhaps the worst outing of Jansen’s career. For reference, on April 11, 2021, Jansen’s cutter had a whiff rate of 50% with the only batted ball having an exit velocity of 46 mph. He retired the side in order with two strikeouts.

The main cause of Kenley Jansen’s struggles the past few years is how he has been deployed by Dave Roberts.  Jansen’s first blown save of 2021, April 7 against Oakland, was perhaps the best indicator of this problem as Jansen was pitching on back to back nights. The myth of ‘Kenley Jansen the iron man reliever’ was born on Thursday October 13, 2016 during game 5 of the NLDS against the Nationals. After Grant Dayton gives up a single to Clint Robinson, his third straight hit allowed, Dave Roberts brings in his closer to shut the door on the Nationals right then and there. Despite some rough patches, most notably back to back walks to start the bottom of the ninth, Kenley Jansen kept the Dodgers’ one run lead intact, throwing a career high 51 pitches in the process. Those heroics gave birth to the idea that Kenley was able to go for multiple innings and on back to back days with no issues. However, what is perceived to be a strength can actually be a weakness and this certainly is Jansen’s biggest weakness. In the last full MLB season back in 2019, Jansen had a 6.43 ERA, 1.36 WHIP, 3.21 BB/9, and 1.93 HR/9 pitching in back to backs. If you remove back to backs from Jansen’s stats that year, his ERA falls from 3.71 to 2.94 which would’ve ranked 35th amongst all relievers in baseball, tied with Taylor Rogers and ahead of other notable closers such as Brad Hand and Ian Kennedy. While these numbers aren’t super impressive from your closer, this was before Driveline helped him fix his mechanics. Even in the blown save in Oakland, Statcast showed that Jansen was not the same pitcher as the night before. His cutter had half the horizontal movement as it did the night before thus leading to the blown save.

Ultimately Kenley Jansen is not the same pitcher who finished top 5 in Cy Young voting in 2017. The cutter isn’t as fast, and it isn’t as firm. The calls for him to be demoted are overblown, but there is a kernel of truth hidden within them. Kenley Jansen isn’t a Josh Hader or Liam Hendriks type where he can go multiple innings, or back to back nights. He doesn’t need to be though, the Dodgers have a bullpen full of incredibly talented pitchers, and multiple pitchers, Blake Treinen, Victor Gonzalez, and Corey Knebel, who all have the trust of Dave Roberts. Even with Knebel going on the IL, Gonzalez and Treinen are still fantastic options to close out games. Let’s not forget that despite the blown save Jansen still has a 2.61 ERA with 1.06 WHIP this year, numbers that are still in line with his career averages. Hopefully down the line, every time California Love plays over the loudspeakers at Dodger Stadium will once again be accompanied by a round of cheers again.

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