In last night's game, Vidal Nuno was gifted five early runs before he even took the mound. The lead carried him through the game and Nuno earned his first win of the season. But before last night, the southpaw was struggling in the rotation. Though he wasn't shelled, his longest outing was his first start of the season where he maxed out at 5.0 innings. Since then, Nuno put up a 4.50 ERA in his first three starts of the year, and his latest start versus the Angels brought his starting ERA down to 3.54.
Compared to last season, the left-hander is throwing nearly one mph harder already, he's striking out batters at a rate much closer to his minor league numbers, but he's also taken a step back with his command. Nuno owns a 4.01 BB/9 thus far, something far off from his minor league 1.7 BB/9. One of Nuno's strength might be his surprisingly high fly ball rate, and for a left-handed pitcher, this works well with the outfield defense in both left field and center field.
It's hard to tell exactly what Nuno will become as a major league starting pitcher. His strikeout numbers have jumped along with his walk rates, and his velocity is increasing, but his starts aren't lasting very long. While we occasionally see glimpses of upside with the left-hander, the Yankees have other options in the pitching staff. This is a win-now Yankee team, and they don't have a couple of months to test Nuno as a major league starter.
The other starting option behind Nuno is Alfredo Aceves, who had just one outing this season in relief of CC Sabathia. After Sabathia stumbled against the Rays, Aceves pitched 5.1 innings of relief, giving up just three hits and earning five strikeouts with no walks or runs. Aceves has a much longer history of major league success compared to Nuno, and his 366.1 innings in the MLB come with a 3.64 ERA and 1.196 WHIP.
While it's debatable whether Aceves is actually a better starting pitcher than Nuno, especially when you consider Nuno's flyball tendency plays so well into the Yankees' defensive strengths, there are other advantages to having a left-handed long reliever in the bullpen. Putting the right-handed Aceves in the rotation along with David Phelps, and eventually Michael Pineda, forces teams to set their lineups to a right-handed starter. If Phelps or Aceves struggle, using a left-handed pitcher in the bullpen to pick up the pieces would put Nuno in a better platoon situation.
At the moment, left-handed batters actually hit Nuno slightly better than right-handed batters, but this comes in just 13 at bats. In a similar small sample size in 2013, Nuno held lefties to a .188/.316/.375 slash. Theoretically, he should hold left-handed batters to lower numbers than right-handers, but that just hasn't happened yet. Regardless, the platoon advantage should show up eventually, and if managers set their lineups expecting the right-handers Aceves and Phelps, Nuno will be a formidable backup reliever when these teams stack their left-handed bats. If managers decide to counter this move, Nuno will at least weaken the opposing bench, and this is the type of advantage Joe Girardi is always looking for.