Leave Kenley Jansen alone

Everyone's favorite party monster/ex-GM Jim Bowden had some bold predictions for Spring Training a few days ago, and one of his predictions was as bold as a jock strap beta tester.¹

Brian Wilson will win the closer’s job for the Los Angeles Dodgers.

I predict Wilson will close for the Dodgers on Opening Day, with Kenley Jansen moving to the eighth-inning setup role. Wilson’s stuff will be even better than it was last season and show flashes that he’s nearly all the way back to prime days with San Francisco.

This will give manager Don Mattingly the flexibility to use Jansen for more than an inning at a time, and in certain seventh- and eighth-inning situations that are often more demanding than the ninth.

This argument does make some sense on its face. Let Jansen pitch in a more versatile role so he can potentially get bigger outs instead of just forcing him to only handle the ninth up one to three runs. It sounds good, but the idea comes apart if you dig into it.

Due to the fact that the bottom of the ninth inning is much more important than any other, the leaders in average leverage index² are almost exclusively closers. Mark Melancon was the only setup man that saw higher leverage situations his team's primary closer, Jason Grilli, and even that was largely because he took over the role for a couple months in Grilli’s absence. If you’re going to have a guy pitch the ninth every team the game is close with a lead, they’re going to see the highest pressure situations by default.

Average leverage index does have a flaw though, it doesn’t consider the strength of opponents faced. Maybe there’s a set of relievers being deployed specifically against the opposing team’s toughest hitters. If this is true, no one is doing it consistently. Baseball Prospectus measures the quality of hitter a pitcher faces and the reliever³ that faced the toughest competition last year was Josh Lindblom. As you go down the list the only great setup man up there is the Yankees’ David Robertson, and the Yankees used him as a traditional one 8th inning guy. Again this is something that sounds nice in theory, but almost impossible to put into practice.

Even if it were possible to use Jansen as a high leverage swing man, Don Mattingly has shown little desire to use him in that role. When Jansen hasn’t held the closer role under Mattingly I count seven occasions when Mattingly deployed him as something other than a pure 8th inning guy in a close game. When Brandon League was creating hits like The Human League, Mattingly paid lip service to using Jansen as closer and League as the setup man in certain situations. He never put this into practice though. There was never a game where League held down the lead in the 8th and Jansen got the save. Maybe somewhere there’s a manager that’s willing to completely uproot modern reliever usage and keep his bullpen from revolting, but Donnie Baseball isn’t that guy.

It’s strange that Jansen the only major reliever that gets this treatment. Several teams have a great setup man backing an elite closer but no one ever suggested that the Yankees have Robertson close while Mariano Rivera sets up, or Jonny Venters taking over the end of game duties for the Braves. If this was a good idea, every team with two good arms should put it into practice, but for some reason⁴, Jansen is the only guy who hears this.

I’m not going to make any proclamations over a reliever’s future. The last time I did that, Joe Torre blew up Jonathan Broxton’s arm 15 minutes later, so I’m just going to leave it at this. Heading into 2014 Kenley Jansen is one of the best relievers in baseball with only Craig Kimbrel as his clear superior⁵. It’s time to recognize him as one of the most valuable assets on the team, that he should pitch the ninth if you aren’t going to completely revolutionize bullpen usage, and let the man win some games for us.

^{1. And as much of a stretch as this simile ↩}

^{2. Average Leverage Index (aLI) measures how much of an impact a plate appearance has on the outcome of the game.↩}

^{3. Minimum 30 innings↩}

^{4. Poorly timed injuries and hot streaks from lesser relievers that made his own team bounce him around.↩}

^{5. The original plan was to remove Jansen’s disastrous first two months of 2011 from his stats to point out how close he is to Kimbrel otherwise, but even without those Kimbrel is way better. Craig Kimbrel is really good you guys.↩}