Back in September 2015, after his 10th major league start, I assessed Aaron Nola’s ability to carve up hitters and economically win ballgames as an emerging top-rotation starter for the Phillies.
Tuesday, after his 19th major league start, Nola sits at 2-2 with a 2.93 ERA this season. His 44 strikeouts and 7 walks indicate a pitcher with masterful command and whiff ability. He’s fourth in the majors in strikeouts, fourth in the majors in WHIP, fifth in the National League in K/BB and eighth in the league in pitcher rWAR (1.2). Extrapolate that over an entire season and you have a 6.4 WAR pitcher (that’s MVP caliber).
So yes, Aaron Nola is still pretty good. Through 19 career starts he’s 8-4 with a 3.37 ERA (3.47 FIP), 8.57 K/9 and 1.99 BB/9. Again, pretty good.
In that September 2015 assessment I concluded that Nola’s fastball (he throws a four- and two-seamer that’s also described as a sinker), curve and command would be enough early in his career (first 30-50 starts), but in time variation would be necessary. Either an improved changeup, or a new tertiary pitch, or a changed approach, would help Nola remain a top-tier starter in the long run.
So while we’re just 19 starts in, are there any signals of this development we can track?
One early signal is the increased use of the two-seamer, or sinker. In July and August of 2015 he was throwing that pitch about 20 percent of the time, compared to 44 percent four-seam fastballs. Things have flipped dramatically; in April the two pitches were nearly equal in usage, and in Tuesday’s start he threw the sinker 46 percent of the time, compared to just 12 percent four-seamers.
And how is that changing outcomes? For one, the sinker has slightly more drop (a difference of about three inches) and slightly more horizontal movement (a bit more inside on righties) than the traditional fastball. And he throws it at the same velocity and release point as the four-seam fastball (in fact, all of Nola’s pitches are thrown at the same release point, though the curve can start a tad higher, but not enough for the naked eye to detect quickly).
Thus the sinker is slowly becoming a strikeout pitch. Already this year (six starts) he’s generated 13 swinging strikes on the pitch, whereas last season (13 starts) he only got seven whiffs on it.
But the sinker isn’t even the biggest signal thus far; that, in fact, is the curveball, which has become a better pitch this season for Nola. This season he’s generated 43 swinging strikes on the pitch, and last year? Fifty-four. That’s partially because he’s throwing it more – this year he’s thrown the curve about 33 percent of the time, whereas last year it was used about 24 percent of the time. With its six-inch vertical drop and 10-inch horizontal movement away from right-handed hitters, it’s an exceptional weapon.
So armed with stellar command, and showing a strong out-pitch (curve) and an improved and more-often-used secondary pitch (sinker), are we seeing Nola’s development move into a new phase?
Here’s where there’s still worry. For one, while the curve and sinker are strong, the traditional four-seam fastball has lost a little luster this season. In April 41 percent of Nola’s four-seam fastballs put in play where hit for line drives, up from the mid-30s for all of 2015. Small sample size still, but it’s a small nugget to remember for now. The sinker has actually generated more fly balls for Nola this season (around 30 percent of all sinkers hit), but in good news, Nola has only surrendered three home runs, a respectable number for six starts.
Then there’s the changeup. Nola isn’t throwing it any more than before; in fact, he’s reduced his changeup usage this season (down from 12 percent last year to about seven percent this year). And it’s no different against left-handers, who would be typical targets for the changeup, which tails away against them. Nola threw a changeup just five times out of 49 total pitches Tuesday to lefties; instead he relied on the sinker (16 pitches) and curveball (18 pitches). That strategy worked last night, as lefties (Matt Carpenter, Matt Adams, Kolten Wong) were 1-for-10 against Nola with a walk (Wong) and a double (Carpenter), which came on a first-pitch fastball on the outside corner. You can’t necessarily fault Nola for that.
Overall this year the changeup remains a negative-value pitch for Nola (0.6 runs above average), but lefties are hitting just .150 against Nola (worse than righties at .191). Lefties have a .219 on-base percentage and .276 slugging percentage against Nola. Of the nine hits (65 batters faced) Nola has surrendered to lefties, one was a home run, two were doubles and one was a triple. He also has five walks against lefties.
Those lefty hitters who have the extra-base hits: Carpenter (2B), John Jay (2B), Daniel Murphy (3B) and Bryce Harper (HR). Jay’s double came off the changeup; Murphy’s triple was a bad pitch, a middle-in four-seam fastball; Harper hit the sinker, and a good one. Just like last year, Nola will have trouble against good lefty hitters, but considering what we’ve seen so far, this isn’t such a bad list of results.
If there are any true issues going forward, it’s that the four-seam is showing to be slightly more hittable in the small sample. But that’s just it: small sample. We’ll have to check back in on that pitch in another nine to 10 starts.
For now, Nola is steadily moving into that next phase of development. The fastball is still very crisp, the curve is a knockout, and the sinker is improving and being used with more skill than in the past. All good signs for a 22-year-old foundation piece for the Phillies.
Information courtesy Brooks Baseball and FanGraphs.
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