Kenley Jansen Is Marvelous

Kenley Jansen certainly hasn’t been ignored around here. Back in June, for instance, Travis looked at how Jansen’s reliance on a single pitch compares to Mariano Rivera’s. And yet, I still feel like we don’t really appreciate just how great Jansen really is. Throughout this postseason, so much of the focus seems to go to Clayton Kershaw and Justin Turner. Or if not them, then colorful characters like Yasiel Puig or feel-good stories like Chris Taylor. Often, Jansen feels lost. Now, maybe that’s just a case of me miscalculating the extent of the coverage he receives or just being far too tired to think straight by the time Jansen gets into games, but I feel like the big righty is a little underappreciated. But if he performs the way that he’s been performing, that may change for good this week.

If you wander over to Baseball Reference, you’ll note that the innings-pitched threshold for their playoff leaderboards is 30 innings. Jansen doesn’t appear on these yet — for his career, he has 28.1 postseason innings — but logic dictates that he’s about to enter them this series, likely this week. Let’s take a look at where he’d rank on some of those leaderboards as of right now.

So, Jansen would rank 10th all-time in terms of WHIP. Not exactly a stat we focus on over on this blog, but impressive nonetheless. And he’s got some pretty good company on this list.

Second is pretty good, I think. (Side note: maybe we also need to go back and appreciate Jeremy Affeldt’s career a little more.) Better than Roy Halladay, Andrew Miller, and Rivera is pretty good. Let’s look at one more.

I think best ever is also pretty good, right? Even if Jansen gets that next 1.2 IP to reach the 30-inning threshold without another strikeout, he’d still have a 14.1 K/9, which would still place No. 1 comfortably on this list.

This all strikes me as quite remarkable — for starters, that Jansen actually on the verge of reaching 30 IP for his postseason career. Craig Kimbrel, for reference, has thrown 10 IP in the postseason, and the two debuted in the same season. Zach Britton has just 4.2 postseason IP. Aroldis Chapman (28.1 IP) and David Robertson (30.0) are right with Jansen, as is Andrew Miller (32.2), but there just aren’t a ton of active pitchers who have amassed that kind of postseason bulk. Sergio Romo has already pitched in three World Series, and he’s still just at 23.1 IP for his postseason career. Jonathan Papelbon has been around since 2005 and has only recorded 27.0 postseason IP, and that’s a total he probably won’t be adding to, since he didn’t pitch in the majors this year. Other relief leaders since 2010 — Koji Uehara (18.0), Greg Holland (11.2), Mark Melancon (10.0) and Dellin Betances (5.2) — fall well short of Jansen. Obviously some of that is opportunity, but Jansen has remained effective throughout the entire stretch.

Of course, we needn’t look at Jansen’s greatness solely through the prism of the postseason. If you clicked through to that previous link, you’d have seen that, by WAR, Jansen has been neck and neck for best reliever in the game with Kimbrel since the two debuted back in 2010. This season, Jansen became one of just 19 relievers all time to put up 3.5 WAR in a single season. Also notable was the fact that Jansen’s 2017 campaign was just the fifth such season since 2000:

While subject in part to randomness, I’ve included left-on-base percentage here for a reason. Of the 7,503 qualified relief seasons throughout history, Jansen’s 2017 season is one of just 64 in which a pitcher had a 90%-plus LOB%.

From a WPA perspective, Jansen’s 5.33 WPA represents the 28th-best season ever, sandwiched right between a Brad Lidge and a Billy Wagner season. Pretty great company.

On a career level, Jansen already ranks 17th overall in terms of WAR. Both he and Kimbrel will almost assuredly pass Robb Nen next year, and if Jansen posts a 2 WAR season like he normally does (he’s posted a two wins or better in five of the past six seasons, and in the other year he posted 1.7 WAR), he could leap into the top 10 all-time, depending on how things go for Kimbrel (and perhaps also for Chapman). Perhaps my favorite part of this leaderboard is that Kimbrel and Jansen have reached their respective levels in so few innings. Right behind Jansen on the WAR leaderboard is Rodriguez, who has thrown more than twice as many innings in his career as has Jansen. A few of the pitchers ahead of Jansen threw more than three times as many innings. And, it’s not just WAR. Jansen ranks 21st all-time in terms of WPA.

Kenley Jansen is a pretty great pitcher. He’s been great in the regular season. He’s been great in the postseason. He’s working on 12 straight postseason appearances without allowing an earned run. He’s essentially posted the best K/9 in postseason history. In this World Series, he’s likely going to be tested. He’s the best relief pitcher on a team facing the best offense in the majors. If he does get the call, it’ll be must-see TV, and I wouldn’t bet against him.