On the whole, relief pitchers are a volatile group, often, it seems, alternating between good and bad seasons—or even good and bad outings.
One might think closers are more reliable, since they're tasked with getting the all-important final three outs. But frankly, even those who throw in the ninth inning aren't immune from shaky appearances every now and then.
And sometimes, even more often than that, as we have seen recently in Boston and Detroit, where both the Red Sox and Tigers recently made it known that struggling closers Andrew Bailey and Jose Valverde will get a break from their usual duties.
(In Valverde's case, that break appears to be a bit more permanent.)
When such shakeups happen to contending teams like the Red Sox and Tigers, it can be particularly unsettling, given the significance of the circumstances. That makes Boston and Detroit two contenders who could be on the lookout for a closer between now and the July 31 trade deadline.
They're not alone, though.
Following the loss of Jason Motte back in spring training, the St. Louis Cardinals appear to have solved their ninth-inning situation, thanks to Edward Mujica (21-for-21 in saves with a 1.97 ERA). Still, if something were to go wrong there, the Cards may entertain the idea of acquiring a closer, should they not want to entrust the role to rookie Trevor Rosenthal.
A similar situation has taken place in Arizona, where the Diamondbacks have been without J.J. Putz since early May due to an elbow strain. Heath Bell has helped prevent a disaster in the desert by converting 13 of 15 saves, but the veteran righty has also been scored upon in each of his last four outings. Putz is getting closer to returning, but neither he nor Bell seems to be a completely safe stopper, so the D-backs may consider closers, too.
But which late-inning arms are expected to be available via trade to help the Red Sox, Tigers, Cards, D-backs and other contenders address their potential needs for closers?
For now, we'll leave out the Rays' Fernando Rodney, Padres' Huston Street, Indians' Chris Perez and Rockies' Rafael Betancourt as possible trade chips given that their teams entered Friday at .500 or better. Should any of those clubs falter over the next month or so, though, you can expect to hear those names on the trade market.
As for the names that may already be on the market—or could be soon—let's take a look.