NEW YORK -- Nathan Eovaldi isn't Noah Syndergaard. He isn't Gerrit Cole or Stephen Strasburg, either. He could be, but he chooses not to be. And it's that choice that has led to Eovaldi's recent string of success on the mound for the Yankees.
Eovaldi throws the second-fastest fastball of any starting pitcher in baseball, a four-seamer that clocks in, on average, at 96.9 mph. However, unlike Syndergaard, Cole and Strasburg -- who rank first, third and fifth in average velocity -- Eovaldi doesn't pound the zone with a majority of heaters. In fact, of the 21 starting pitchers who average 93 mph or greater on their fastballs, Eovaldi is the only one who throws his less than 50 percent of the time.
Instead, Eovaldi mixes in a steady dose of splitters, sliders and curveballs -- along with his four-seamer. According to Pitch/Fx data, 49 percent of his pitches are fastballs, 25 percent are splitters, 19 percent are sliders and only 7 percent are curveballs. This variety has gone a long way toward keeping batters off balance recently. Over his last four starts, he's allowed just six runs in 25 innings, earning four wins and dropping his ERA nearly two full points.
Yankees manager Joe Girardi has noticed the increased variety in Eovaldi's arsenal and said he believes it's what has pushed Eovaldi into the realm of potentially being the Yankees' most reliable starter.
"I think the days that he pitches well [happen] when he mixes [his pitches]," Girardi said. "You can't just rely on fastball in this league, because guys will catch up and make adjustments. ... The big thing is that he's got at least three of his pitches going. You're not always going to have four."
Eovaldi used to be the kind of pitcher who relied solely on his fastball. For the first four years of his career, Eovaldi was a two-pitch pitcher. Between his debut in 2011 and his last year in Miami in '14, Eovaldi threw his fastball 65 percent of the time -- a mark that would be among the highest in baseball today.

However, Eovaldi always felt he needed another pitch in his repertoire. He had his slider, which he used about 22 percent of the time, and his curveball, which was never going to develop into a primary pitch. But he felt the one pitch that had always eluded him was a changeup. So with two games remaining in the 2014 season, after having tinkered with a few different styles of changeup, Eovaldi and then-Marlins pitching coach Chuck Hernandez settled on a splitter.
A splitter, easily explained, is thrown with a grip similar to a two-seam fastball -- just with the index and middle fingers outside of the seams and a little more pressure applied to the ball. The effect, at least with Eovaldi, is to break the opposite way of his slider, darting down and in to right-handed hitters. Adding the splitter came with immediate results: Eovaldi allowed just four runs in 13 innings after rolling out the pitch in 2014. So when the Yankees acquired the right-hander before the '15 season, Eovaldi said pitching coach Larry Rothschild wanted him to shift his focus to perfecting his splitter.
This season, Eovaldi has almost achieved that. Opponents are batting .187 versus the pitch, whiffing 17 percent of the time. To put that in perspective, Eovaldi has induced more strikeouts with his splitter than his fastball this season -- and he's thrown more than twice as many fastballs.
As good as his splitter is, it isn't the pitch that his approach hinges upon. Eovaldi agreed with Girardi's assessment that he thrives because of his variety. But he also said he's developed enough as a pitcher to really only need two pitches on any given night, as long as one is the heater.
"I feel like, at times, I can get away with just two now, as long as my fastball is one of those two -- where I'm able to work it both inside and outside," Eovaldi said. "Then, I'm either [going] to have the splitter or slider to work with."
But to catcher Austin Romine, who has caught five of Eovaldi's last six starts, just because the fastball might be his most important pitch, that doesn't mean he should throw it more often.
"How many games has he won in a row? Three? Four? Something's working," Romine said. "When you talk to the guy, it's whatever you need to throw to get a guy out is what we're going to throw. I know people are saying he throws 100 and stuff like that, but I think he's just [thinking] along the lines of, 'Let's get everybody out and let's do it quick.'"