The Yankees Bullpen Probably Won’t Be Any Better

Your immediate reaction to the Aroldis Chapman trade was right on. The Yankees have assembled something silly, a three-headed bullpen monster to rival any in the history of the game. On talent, Chapman, Andrew Miller, and Dellin Betances are three of the five or ten or so best relievers in baseball, and now if this plan comes together, one will hand the ball to the other, who will then in turn hand the ball to the other. While the 2016 Yankees aren’t going to feature a roster full of All-Stars, it’s going to feel like a pitching staff full of All-Stars in the most important moments, and that’s not going to be any fun for half the people watching.

There’s something important to be said, though. On talent, the 2016 Yankees bullpen should be better than the 2015 Yankees bullpen. Yet on performance, it’ll be hard for this coming year’s group to improve on the group that was. You’ve probably seen some of the numbers, like how the Yankees were 66-3 when leading after six, and 73-2 when leading after seven. Honestly, that probably already says enough, but we can make use of some of our own statistics. Whether you go superficial or analytical, last year’s bullpen almost always got the job done, when the job was important.

Obviously, Miller is a returner. And Betances is coming back. Chapman effectively replaces Justin Wilson, and there’s not a person on the planet who’d prefer the latter over the former. Even Wilson’s own family would have to apologize and hope that Justin wouldn’t be offended. He wouldn’t be, because he knows Chapman is something extraordinary. When you’re going into a season, you want Chapman. But looking back on last season, Wilson overachieved. That’s the point of comparison here.

Using the Baseball-Reference Play Index, I looked for the top pitching performances in what they define as high-leverage situations. I set a minimum of 50 batters faced, and then I sorted in ascending order of OPS allowed. The very top of the list:

1. Justin Wilson, .377 OPS against
2. Kenley Jansen, .387
3. Wade Davis, .392
4. Andrew Miller, .420
5. Brad Ziegler, .429

Wilson’s overall OPS against was .602 — good, but not outstanding. Yet we care less about what happened with him on the mound in less-important situations. He was supposed to get big outs, and when the outs were big, he just about always got them. You can’t really expect to improve on that .377.

Let’s take a quick step back. Last year, 26 Yankees appeared as relievers. Just three of them had an average leverage index above 1.0. That was the Miller/Betances/Wilson trio. Nine more had an average leverage index between 0.5 – 1.0. That leaves 14 with an average leverage index below 0.5. The top group yielded 2.3 runs per 9 innings. The next group yielded 5.0, while the lowest group yielded 5.4. In one sense, the Yankees bullpen was valuable; in another sense, it gave up more than four runs per 9. The key was that the Yankees could decide which pitchers pitched in which situations.

So by WPA, the Yankees bullpen ranked third, at +8.5. By WPA/LI, it ranked 13th at +1.5. The first one is the more important one. The first one is a more accurate reflection of how the bullpen performed as far as preserving close scores was concerned. The group was worse when situations mattered less.

Looking at the past 20 years in the major leagues, there have been 596 individual team-seasons. The Yankees bullpen just ranked 25th in WPA. It ranked just 284th in WPA/LI, and here’s where the difference is — they ranked second in Clutch. Because the bullpen was so lopsided, that worked in the Yankees’ favor, as these numbers go. Now let’s say we’re certain this year’s Yankees will have a top-three bullpen. We can’t be that certain, but let’s just say. Let’s say they’ll finish in the top three in WPA. Over the past decade, top-three bullpens each year have averaged a WPA of +8.4. Last year’s Yankees, again, finished at +8.5.

It’s possible to be better. Last year’s Yankees finished behind the Orioles and the Royals. And in 2012, the Orioles bullpen finished with a WPA of +13.9. Of course there’s room to take a step forward, but there’s at least as much room to take a step back. Last year’s Yankee bullpen performance was outstanding, and they’d be happy this coming year to just repeat. It’s worth noting that, while the top three are fantastic, Wilson is gone. Adam Warren is gone. You figure Betances or Miller (or Chapman) might regress some. Chasen Shreve isn’t reliable yet. Bryan Mitchell isn’t reliable yet. Branden Pinder isn’t reliable yet. The bullpen has three amazing arms out of a number far greater than three.

Here’s one way to see the effect of a great bullpen. We’ll go back to using those last 20 years. Teams with bullpen WPAs north of 10 have averaged 96.5 wins. Teams with bullpen WPAs between 9 – 10 have averaged 94.9 wins. Teams with bullpen WPAs between 8 – 9 have averaged 92.8 wins. Teams with bullpen WPAs between 7 – 8 have averaged 94.1 wins. Teams with bullpen WPAs between 6 – 7 have averaged 89.8 wins. Don’t forget that last year’s Yankees technically made the playoffs, if ever so briefly, and theirs was otherwise an underwhelming roster. If the bullpen does indeed turn out strong, the Yankees will have a great shot at returning, and then, of course, once in the playoffs, the top of the bullpen can pitch even more. I don’t need to sell you on relievers. You know about relievers.

Maybe I should’ve said this before, but now that we’re at the end, it has to be said that last year’s Yankees were no longer relevant as far as future plans go. As soon as the season ended, that was it. The performances essentially disappeared. The Yankees didn’t go into the Chapman trade trying to build on last year’s bullpen performance. They went into the Chapman trade projected for an inferior performance, due to regression, and due to the absences of Wilson and Warren. Sure, it feels like the Yankees won’t easily be able to improve relative to 2015, but that’s not the right comparison point — they’re improved, relative to what would’ve been expected. That’s what’s most critical. Chapman makes the Yankees better, compared to the Yankees without Chapman.

For the roster, it was a good move. And now the bullpen looks great. Maybe even something more than that. Compared to the Yankees before the Chapman move, these Yankees are going to have stronger relief. Just don’t expect them to have stronger relief than they had in 2015, once you take leverage into account. The bar was placed at a very high setting, and that bullpen in large part helped give the Yankees a chance at the championship. They’d love for this year’s bullpen to do the same.