With Ron Mahay suffering a season-ending injury and Jose Mijares out for at least a few weeks, the Twins spent the week bargain shopping for left-handed relievers. First they went dumpster-diving and pulled Randy Flores from the Rockies for free. Flores was appropriately available for nothing, as he's shown little ability this year, posting a FIP and xFIP over 5.00. For his career those numbers are slightly better, to the tune of 4.37 and 4.49 respectively. And, as Aaron Gleeman pointed out in detail, he doesn't even fit the profile of a lefty reliever, as his career (and 2010 season) statistics give no evidence of the traditional platoon split.
For those two reasons, the Twins' next stop was the thrift store, where they picked up a better left-handed reliever who has demonstrated a significant ability to get out left-handed hitters. While Flores is a questionable addition, as he may not even be better than Glen Perkins, Fuentes will definitely help out the Twins bullpen. Fuentes hasn't been especially effective since his transition to the American League, but he has continued to overwhelm lefties. This season, in an admittedly small sample, he's struck out more than a third of the left-handed hitters he's faced and allowed a hitting line of just .132/.209/.158. Last season, and his career in general, show a similar trend, although the strikeout rate and opposing hitters' line isn't quite as impressive.
Of course, since we don't know who the Twins gave up yet, we can't properly evaluate the deal. Assuming it isn't anybody significant, however, this move will improve the Twins bullpen and thus is a good transaction. The small advantage this gives the Twins isn't likely to be a difference maker, but it will leave even less to chance. On the other hand, the Twins have once again screwed my fantasy team, first trading for Matt Capps and removing Jon Rauch from the closer's role (Rauch was on my team), and now snatching Fuentes from his closing role, who was also on my team. In fact I had just traded for Fuentes last week. Oh well.