The closer battle in Florida might seem like just another notch in the ‘relievers are just failed starters’ way of thinking. Both the incumbent, Leo Nunez, and the challenger, Clay Hensley, have started games at different points in their careers. Given the fact that manager Edwin Rodriguez has already said that Nunez will probably get his job back, it’s not a great idea to drop Nunez wholesale. How much of a threat does Hensley actually represent, though?
His present rates look nice – he has a 9.47 K/9 and 3.25 BB/9 that are both above-average even for relievers – and his luck stats don’t seem to suggest a major regression coming (.286 BABIP, 77.7% LOB, 2.88 FIP). Counting on them to continue in the face of his career rates (6.34 K/9, 4.02 BB/9), however, seems dicey at best. The nice groundball rate (51.9% this year, 52.7% career) looks steady and repeatable, and should always give him a stable level of effectiveness to fall back on.
But it’s the major jump in strikeout rate that has made him a closer option. This is the first year he’s spent the entire year in the bullpen, so a jump could be expected. Jeremy Greenhouse found that moving to the bullpen can give you about 0.7 MPH of fastball velocity, and cited research from Tom Tango that you’d expect a reliever to gain about 17% K/PA in the switch. We haven’t seen the velocity jump for Hensley – he has been showing an 88.7 MPH fastball this year, 88.7 MPH career. Hensley has also seen his strikeout rate jump almost 50% over his career rate, so he’s obviously changed something other than his throwing schedule.
Looking at his pitching mix, one thing jumps out immediately. Hensley has gone from featuring his slider as his best second pitch (8.8% this year, 19.8% career) to focusing more on his curveball (22.4% this year, 9.9% career). In general, he’s throwing his secondary pitches more often, as he’s also upped his changeup usage (21.2% this year, 12.5% career). While the changeup and slider are close enough in velocity that the two pitch f/x systems on our site see them differently, the reduced use of the fastball looks legitimate. Given the linear weights on his slider (+16.7 runs career) and curveball (+10.1 runs career) compared to his fastball (+5.3 runs career, -10.7 runs 2008-2009), this seems like a legitimate change in pitching approach – to his benefit.
Still, as strong as his work has been this year, Hensley has only put together 63 innings at this level of play. It’s the first time since his rookie year in 2005 – another year in which he primarily relieved at the major league level – that he’s put up an FIP under four. To compare, Nunez has put up sub-four FIPs in two of the last three years, and he’s had almost a strikeout per inning over his last 120 innings. Still, given the fact that Nunez has a career strikeout rate (7.04 K/9) that is comparable to Hensley’s (especially once you take out this year’s 9.64 K/9, a career high for Nunez), and owns a similar history of moving from the rotation to the pen, it’s possible that Hensley is next year’s Leo Nunez.
This year, though, you have to give some credence to what the manager says. It also makes sense to take the reliever with the larger sample size of success if you are looking for saves in Florida.