By R.J. Anderson //

If you guessed that Leo Nunez would be the better pitcher through May than Jonathan Papelbon, then congrats, but you should really use that soothsaying ability on more profitable ventures. It’s true, though, we’re just over one-third of the way through the season and Nunez has 12 saves, a 2.28 ERA, and better strikeout, walk, and home run rates than the venerable Boston reliever.

The former Royal, acquired by the Marlins after the 2008 season for Mike Jacobs, does it without the prototypical power closer stuff. Yes, he still features a blazing fastball, one that tops 94 miles per hour on average. It’s his secondary stuff that differentiates him. Nunez used to rely on a slider, but the Marlins have coaxed him away from throwing it. Instead Nunez leans heavily on a change-up that sits fewer than 10 ticks away from his heater. FanGraphs has his change-up worth 3.04 runs per 100 pitches thrown. That places it among the most effective pitches in baseball.

Roughly 13% of Nunez’s pitches have resulted in swings-and-misses. If that number improves or holds steady through season’s end, it will represent a career high, breaking the high he set just last season. That’s not the most interesting alteration in Nunez’s game, though. Instead that honor goes to Nunez’s newfound control. His career walks per nine innings rate is 2.86; this year he’s down to 1.90, a number which would net a career best.

Yes, Nunez is on pace for the best season of his career. In 2008, Nunez’s previous best season, he threw nearly 50 innings and posted a 2.98 ERA. Still, his strikeout (4.84) and groundball (39.1%) rates were uninspiring.

Now, though, Nunez’s change has given him a whole new lease on upper-tier life. Nearly 50% of his batted balls against this season have been grounders. When combined with his strikeouts and walks, Nunez has now emerged as one of the top relievers in the National League.