Why is Edward Mujica still on the Oakland A's?

In early May, the Oakland A's were still trying to compete but their bullpen was making that goal difficult. In a shrewd move, they picked up the out-of-favor Edward Mujica from the Red Sox for virtually nothing. Mujica had experience, some fairly recent success, and strong K:BB credentials. He got off to a nice start, with five scoreless outings to begin his A's career, but this is 2015 so he was hit by a line drive and suffered a fractured thumb that knocked him out for a month.

Since his return, Mujica just hasn't been the same. He's got 11 strikeouts to only one walk, but he's been supremely hittable, allowing six homers and 25 hits in 17 innings en route to a 7.41 ERA. He's blown two saves in six save situations (1 save, 3 holds), and also picked up a pair of losses in tie games after surrendering the go-ahead runs. He's been bad at holding leads, and he's been bad in general ... so naturally, he has been serving as the team's primary closer since Tyler Clippard was dealt.

What gives? Even with the team moving to more of a closer-by-committee in recent days, as evidenced by Drew Pomeranz earning the save against the Dodgers on Wednesday, why is Mujica in the mix to close games at all when he might be the worst pitcher in the pen? Why is he even on the team, given that he'll be a free agent at year's end, has virtually no chance of being on the 2016 roster, and isn't even helping on the field right now? One possible theory is that it has to do with arbitration.

Saves are expensive in arbitration. The arbiters are not authorities on baseball metrics, and the save is easily the most overvalued stat in the entire process. You may remember, back when the A's acquired Jim Johnson and his $10 million salary, that the conversation turned to how the team could earn back that excess money by keeping their pre-arbitration pitchers from racking up big save totals. The logic is that a player's first-year arbitration reward is used as the starting point for the next year's conversation, and so preventing him from picking up too many overvalued saves would pay dividends not only the next winter but every year after that until free agency.

Furthermore, given that there isn't even a consensus that your best reliever should be saved strictly for ninth-inning save opportunities, an addition like Johnson might free up a manager to insert his actual top relievers (like Sean Doolittle or Ryan Cook, at the time) into the actual crucial situations that so often pop up in the seventh or eighth frames. You'll pay $10 million for Johnson today, but you could save $7 million down the road in cheaper settlements with Cook or Doolittle, making Johnson more like a reasonable $3 million layout in the long run while also making the team deeper and better. The plan didn't work out perfectly, since Johnson exploded and Cook eventually burned out, but it did get Doolittle signed to a team-friendly long-term deal right before he became an All-Star closer ... but then he got hurt and missed this whole year. Dammit A's.

Mujica, at this point, is like a small-scale version of Johnson. He's making a little less than half the salary, he's only being relied on to help close for a couple of non-competitive months, and the pitchers he's taking saves from are not All-Star-level guys. This wasn't always Mujica's role in Oakland -- he was originally supposed to be a legit setup man on a team trying to contend -- but it's the reason he's still here when his on-field presence otherwise makes no sense.

Who is losing future money because of Mujica? The best bets are Pomeranz, who is entering his first arbitration year, and Fernando Rodriguez, who is entering his second. Based on past precedents, each save could add a five-digit boost to an arbitration reward, so adding 5-10 saves to the lines of either of those guys could easily add mid-six-digits. If Pomeranz costs an extra $500K next year, then he'll cost that much extra each of the two following years too, meaning a total of $1.5 million in extra salary simply because he closed out some games down the stretch for a last-place 2015 team.

It wouldn't be quite as bad for Rodriguez, who only has two more years of arbitration left, but it could still mean an extra $1 million all told. If you give those shots to a pre-arby guy like R.J. Alvarez, you'll have a multi-million dollar penalty similar to the Pomeranz situation, and I don't need Scribner, Abad, Otero or Venditte to close badly enough to care if they get that role. Pom, Rod, and R.J. are the guys I actively want to see finishing games, but retaining Mujica keeps all of their salaries down without costing the team anything meaningful on the field.

That's why Mujica is still here, to pick up some saves in the least costly way possible. It doesn't matter if he blows a few along the way, because the team's win-loss record is irrelevant at this point -- that doesn't mean I want to actively try to lose games, but it does mean I'm willing to sacrifice some marginal WPA in exchange for salary relief down the road. I thought it was telling that, in the ninth and 10th innings of a tie game at home on Tuesday, the A's didn't turn to Mujica at all -- the home team would normally be willing to use its closer in such a situation, with no remaining possibility for a save, but perhaps it was precisely because there was no longer a save on the table that Mujica wasn't called on. After all, he's there to collect saves, not help win games, and you don't bring arguably your worst reliever into an extra-inning game if you don't have to.

There is one more downside: While we wait for rosters to expand in September, there are several pitchers stuck in Triple-A whom I would love to see, like Alvarez and Arnold Leon and Ryan Dull. This strategy is costing me a few weeks of those players, and it's also costing the other closer candidates like Pom and Rod a chance to gain a bit of experience in the role. But realistically speaking, no one on the current roster figures to become a serious closer anyway, especially with Doolittle looking like his old self on his current rehab assignment, so it's not like anyone's development is being seriously hindered. Pom and Rod are still pitching high-leverage innings, and those Triple-A guys will get their shots next month.

We will continue to cringe every time Mujica is brought into a game, especially in a save situation. But rest assured, there is value to be gained by his presence, as long as you close your eyes when he's actually on the mound.