Charlie Furbush is dead.
Well, not really, but his tricep hurts, so he may as well be. Furbush has long been the Mariners' left-handed reliever of choice, entering late in games to neutralize some of the league's toughest left-handed batters with his luscious beard and sweeping breaking ball. We don't quite know how long Furbush may be sidelined, but considering it's an arm injury and he was on the DL for the last half of 2015 with another arm ailment, we have the right to freak out and burn shit down.
The Mariners have a few options to fill in for Furbush should he need to take some time to
left right himself. First, Vidal Nuno has already been working as a reliever this spring, and he'll be expected to take on some tougher lefties this year. Nuno, as both a starter and a reliever, has held lefties to a .261 wOBA over his career -- compared to .245 for Furbush. Overall as a reliever, Nuno's K/9 jumps to 9.20, and his only issue in the bullpen has been the homers, and some of that is due to playing in Arizona and New York prior to landing in Safeco field. Nuno's best tool may be his ability to pitch multiple innings, but if he's needed as a quasi-LOOGY, so be it.
Also demoted to the bullpen is Mike Montgomery, who would be a strange fit to neutralize lefties, since his stuff doesn't neccessarily play up against same-handed hitters. Monty's changeup is his best offspeed pitch, which tends to have a reverse platoon split, so he's only truly suited to be a long reliever.
David Rollins is also floating around, throwing 93 and getting in trouble for drugs. In his brief appearance in the majors last year, Rollins was not used as a LOOGY, facing two times as many righties as lefties. Now that he's no longer a Rule V pick, the M's may want to work with Rollins in the minors instead of forcing him to the big leagues.
The most fitting replacement for Furbush is a man already in camp, and he doesn't throw left-handed: Joel Peralta. The nearly 40-year-old reliever works entirely with an arsenal that works well against opposite handed hitters: a four-seam fastball, a splitter, and a curveball. If you look at his career, Peralta hasn't had a platoon split, but if you look at just 2011-2015, Peralta has consistently done better against left-handed hitters than those of the right-handed persuasion. For the most part, Peralta seems toast; but in a strange new role, perhaps he has the ability to be an asset to the team.