Mariners Acquire Adam Warren for Role He Deserves

As reported by the indefatigable Ken Rosenthal and Emily Waldon of The Athletic, the Seattle Mariners acquired relief pitcher Adam Warren on Monday afternoon from the New York Yankees in return for bonus slot money.

Is it possible for a bullpen to be too good? Obviously, at some level, that’s a silly question: no lead is 100% safe and, consequently, a team should never stop surveying what it has. But there’s also the question of utility. Any given club is bound to play only so many high-leverage innings. While you’d rather have a good reliever in the game than a poor one, the stuff you can get in return for that good reliever may simply be more useful to your franchise. Warren has been used mainly in low-leverage scenarios this season. Consider: of the eight Yankee pitchers primarily used in relief this season who have thrown at least 20 innings, Warren’s entered the game in the second-least crucial situations overall, ahead of only A.J. Cole, who has more swingman-type utility than Warren.

Chasen Shreve has already been traded by the Yankees for similar reasons, Zach Britton’s arrival in the Bronx only making the competition for those high-pressure situations more fierce. Tommy Kahnle is still standing by if the team loses a reliever and there’s still depth remaining, including J.P. Feyereisen, who continues to refine his control, and Raynel Espinal.

Just to illustrate how Warren’s skill are wasted by using him in the low-leverage innings available, just compare his performances to other relievers with 20 innings pitched and a game-entrance LI with 0.1 of Warren.

With a combined ERA of 3.96, this group hasn’t performed terribly by any means — actually better than the MLB average for relief pitchers of 4.06 — but that’s not even enough to get their collective WPA above zero. It’s a list largely of castoffs, a few LOOGYs, and some young pitchers getting their feet wet. To acquire most of this group wouldn’t take much in return and Warren is among the best pitchers listed above. Of the top 50 relievers in WPA, Robbie Erlin is the only member of this group in attendance and the top 75 only adds Tony Sipp, who’s mostly used based on the handedness of the opposing batter rather than particular game situations. The Yankees simply don’t require a pitcher as good as Adam Warren for the role in which they’ve used Adam Warren.

Summary version: Adam Warren is really good but has been used in such a way that the difference between a really good pitcher and an adequate one is minimized.

In this case, the slot money makes sense for the Yankees, having cleared out a few interesting prospects for Zach Britton and some organizational depth for J.A. Happ. This helps the Yankees restock that cupboard, so to speak. There’s an important misconception with how some people consider the trading of slot money. For example, when the A’s acquired Jeurys Familia, the Mets acquired $1 million in international slot money, probably more important in the end than either of the actual prospects involved. Occasionally you see people treating it as they would that same amount of actual cash changing hands, when in fact, it’s much more valuable. A million dollars spent on major leaguers isn’t that valuable in the big picture. But being allowed to spend $1 million on amateurs is, in fact, far more valuable than regular ol’ cash.

For the Mariners, it’s been a fairly quiet deadline so far for the Man of a Thousand Trades, Jerry DiPoto. Zach Duke was also acquired at nearly the same time as the Warren trade, a move that will be examined by my colleague David Laurila. Might as well get the matching set: who buys a salt shaker without also getting one for the pepper, too? (Now I have to figure out whether lefties are salt or pepper, which is the price I pay for making a bizarre analogy.) Seattle’s bullpen wasn’t suffering before, of course, but with Warren and Duke added to the previous acquisition of Sam Tuivailala — the only MLB name I can’t spell from memory now that Matt Tuiasosopo is out of affiliated ball — the FanGraphs Depth Charts now rate the team’s bullpen as the fourth-best in baseball. My standalone ZiPS projections are close to that, ranking them sixth rather than fourth.

Seattle’s bullpen isn’t full of household names like that the Yankees’, but it’s one of the deepest in the majors now and ready to go deep in the playoffs. With only one realistic team to beat out, Seattle can afford to make moves that look ahead to October. Oakland could still beat out Seattle, but it likely won’t be because of the pen. The Yankees lose a good arm, but one that was largely redundant, the slot money giving the team more chances to make good on their minor-league losses this week. Or maybe another move yet-to-come?