David Phelps remains one of the most overlooked pieces of the Yankees' pitching staff. In 2012, Phelps put together a solid rookie season where he pitched to a 3.34 ERA in 99.2 innings. His 8.7 K/9 that year surprised most fans, as he was hardly a strikeout pitcher in the minor leagues. In 2013, Phelps struggled in the beginning of the season, but once he moved to the rotation, the right-hander only had two truly poor starts out of twelve games. Phelps again opened up the 2014 season with some rough appearances out of the bullpen, but he's since been extremely efficient as a reliever, and showed last night that he can still remain efficient as a starter.
What's made Phelps a bigger success than we expected were the strikeouts. Despite the unusual uptick in his rookie season, Phelps has continued to put together above-average strikeout numbers. The pitcher earns these strikeouts in a number of ways, as he sports a good changeup and a strong curveball, but Phelps does not have much of a swing and miss pitch. Phelps owns a very low swinging strike percentage (4.6% in 2014) and he earns strikeouts on many strike-threes looking. While this is often a sign that a pitcher will regress when batters decide to get more aggressive, batters have failed to adjust to him over the last three seasons.
Phelps has also been successful by generating the right type of poor contact. In situations where Phelps needs a fly ball, he usually pounds the zone with his four-seamer, and when he needs a ground ball he throws the sinker, both of which generated their respective batted ball type 6.5% of the time in 2013.
But in 2014, Phelps has been far more successful than he was in his previous seasons. While you can partially attribute this to small sample size, Phelps' velocity has improved rather dramatically from 2013. According to Brooks Baseball, Phelps has gained about one mph on both his four-seam and two-seam fastball, as well as two mph on his changeup, slider, and curveball. Along with the velocity, he's also throwing his pitches with considerable more movement. His four-seamer and changeup have an inch more movement into right-handed hitters, his sinker has gained about a half an inch of movement both horizontally and vertically, and his slider is showing two inches more horizontal movement away from right-handers and an inch more vertically.
Overall, Phelps is throwing harder and spinning the ball faster. While this could be a product of his shorter relief work, Phelps' start against the Angels was his best showing of the year. Phelps averaged nearly 93 mph on his four-seamer against the Angels, and maxed out at just under 95 mph. While it's odd to gain velocity as a starting pitcher, the weather in Anaheim combined with increased strength as the season matures likely contributed to his velocity jump.
And as the weather warms in New York, it'll be interesting to see how hard Phelps ends up throwing by mid-summer. Though it doesn't necessarily mean that he'll be successful, the improvements in both velocity and movement correlate well with his now 10.06 K/9.