Something might be wrong with Kenley Jansen

In recent postseasons, one of the Dodgers’ main mantras has been “The Dodgers can go as far as Kenley Jansen will carry them.” When Jansen was in his hall-of-fame caliber peak, that was certainly true, and it was also a statement on the general lack of depth in the rest of their bullpen (2017 excluded).

For the first half of this shortened season, that statement sounded pretty good. Jansen won the reliever of the month award in August, a month in which he pitched 11-2/3 innings with a 1.54 ERA, striking out 19 of the 44 batters he faced. Most importantly, his cutter had its signature action:

However, Jansen had well-publicized issues down the stretch, posting a 6.52 ERA in September while allowing a .317/.391/.439 batting line. At first, some of the bad results could be attributed to bad luck, but recently a new problem as popped up.

Below is a chart of Kenley Jansen’s average cutter velocity in every outing since 2018. His average of 88.1mph last night was the lowest he’s had in any appearance of his career:

This chart includes 2018 because that was the last time Jansen had significant velocity concerns. As Chad wrote about in The Athletic at the time, this velocity dip was almost entirely mechanical in nature, relating to recovery from a leg injury, and the above chart shows a quick rebound to his normal 92-94 range after some concerning games to start the season.

Jansen also opened the 2020 season with a velocity dip, though much of that can be attributed to his slow summer camp start. Once he had what approximated a normal ramp-up period, the velocity recovered once again. Perhaps these previous velocity issues could be a source of some hope going forward, that Jansen has rebounded quickly from stretches like this before.

What makes Jansen’s velocity dip so alarming this time is how sudden it has been, and how it has been trending in the wrong direction:

That’s four outings in a row in the 88-89 mph average range after a full season between 90-93.

Jansen’s cutter absolutely can be effective at 90mph, as his last pitch of the night showed:

This is classic Jansen, with late and sharp break above the top of the strike zone. The pitch was only 89.9 mph, but it was effective due to placement and movement. However, most of the cutters Jansen threw last night looked more like this:

That pitch has movement, but the break isn’t as sharp and the location was wrong. Jansen has been struggling with the command of the cutter, and last night he missed the zone with some 86mph looping cutters and got too much plate with some at 89. The ingredients for successful pitching are both velocity and location, and for the most part last night Jansen’s cutter had neither.

Even the Dodgers are concerned:

Dave Roberts expressed some concern about Kenley Jansen’s stuff tonight. Jansen’s velocity was down, and Roberts noted that some of his cutters lacked “teeth.” So.

— Pedro Moura (@pedromoura) October 1, 2020

However, unlike in previous playoff runs, the Dodgers have a very deep bullpen this season. Some combination of Brusdar Graterol, Jake McGee, Victor Gonzalez, and Blake Treinen (who, to be fair, also struggled significantly down the stretch) can step in to take Jansen’s place if required. The Dodgers don’t need to wait on Jansen to figure things out when they have other good options already on the team.

It almost doesn’t matter if Jansen’s issues are mechanical like they were a few years ago or if he is actually hurt. If he continues pitching like he did last night, or like he has over his last few outings, the Dodgers can’t really afford to wait for him to improve. The Brewers are a bad offensive team, but should the Dodgers advance, much more threatening bats will be waiting. And unlike previous years, the Dodgers can go further than Kenley Jansen can carry them. Being decisive in situations like these has not been one of Dave Roberts’ strengths over the years, but Jansen’s struggles might force him into making a decision sooner rather than later.