When the Pirates announced their probable starters for the series against the Nationals, it wasn’t much of a surprise that the group included Chad Kuhl. The right-hander will make his fourth career start on Sunday, following Francisco Liriano and Gerrit Cole, the latter of whom will be returning from the disabled list.
For now, Kuhl is the only remaining member of the wave of recent starting pitching prospect promotions, with Tyler Glasnow and Steven Brault having returned — at least technically — to Indianapolis, and Jameson Taillon expected to return from his break shortly after the second half begins. Whether Kuhl remains in the rotation for a longer period is an open question, particularly as the Pirates are reportedly considering trading Jon Niese.
His most recent start last Saturday night was highly memorable, though for reasons having little to do with Kuhl’s performance on the mound. Manager Clint Hurdle was aggressive in getting Kuhl out of the game with only one out in the third inning. It was his shortest outing since his final start last season, in which he allowed seven runs (four earned) in 1.2 innings.
Earlier this month, we took a closer look at Kuhl’s sinking fastball, and its potential effectiveness relative to other pitchers throwing similar pitches. After Saturday’s start, the consistent feedback from Kuhl and manager Clint Hurdle was that Kuhl needs to do a better job of keeping the ball down in the zone.
“You can go back and re-watch where the pitches are, I’m just up,” Kuhl said that night when asked why he had struggled to generate as many ground ball outs in four starts for the Pirates (0.63 GO/AO) compared to the success he has had at doing so in the minor leagues (1.63 career GO/AO).
I decided to take Kuhl up on the suggestion to revisit some of those pitches to see if that was, in fact the root of his problem. Here is a simple chart of all of Kuhl’s fastballs and their location as tracked by the Statcast system:
You can see clearly from the chart that too large a portion of Kuhl’s pitches, vertically speaking, are in the middle of the strike zone or above, particularly up and to his pitching arm (right) side of the plate. There are not nearly enough pitches in the bottom three zones, which would be most likely to generate ground balls or quality called strikes.
Kuhl has had 34 fastballs put in play in his four starts, 21 of which have become outs (including one sacrifice fly and one sacrifice bunt), and 13 of which were hits. For this analysis, we’ll consider anything in the middle of the zone or above “elevated,” and the rest “down,” setting aside whether the pitch was in or out of the strike zone. Here are the numbers:
These are admittedly very small samples, but you can see that Kuhl has indeed been more effective when he’s been able to work down in the zone. This is in spite of the fact that there hasn’t been a large difference in his average exit velocity when he elevates (93.9 MPH) as opposed to when he keeps the ball down (93.2 MPH).
Our own Alan Saunders asked Kuhl on Saturday what mechanical explanation there was for him to be leaving pitches up, and he offered that he can become “too rotational,” making it difficult to get on top of the ball and create the fabled downward plane trajectory that keeps the ball heading toward the bottom of the zone.
I asked Eric Fryer that night for his perspective on Kuhl’s performance, and he helped clarify his early struggles a bit more.
“When he says he’s being too rotational, it just means his arm’s kind of dragging to the side,” Fryer said, reinforcing that Kuhl’s inability to get on top of the ball was the primary issue as he saw it from behind the plate on Saturday.
“At lot of times it’s easier said than done to fix it mid-game. The ball was coming out good, it was just up in the zone, not getting the sink it normally has,” said Fryer. “When we executed our pitches, we got ground balls for the most part.”
The issue with Kuhl’s arm angle becoming too shallow is tricky to see in the Statcast data, though his balls in play on Saturday that went for hits were indeed released at a lower point (5.73 feet) than his strikes and outs (5.8 feet). That means a difference of slightly less than an inch, but that can certainly have an impact on what the batter sees as the ball approaches the plate.
This chart from Brooks Baseball is in line with the Statcast data:
Again, we’re talking about a very slight difference here, but in a motion as precise as a pitcher’s delivery, these marginal changes are important.
It seems, then, that there is indeed some truth to the arm angle hypothesis, and there is certainly no argument that Kuhl’s struggles with keeping the sinker down in the zone are leading to some difficult outings in the early going.
When I asked Clint Hurdle on Saturday if he thought that Kuhl’s elevation issues were due in some part to excess adrenaline, he agreed with that premise, and it’s reasonable to suspect that Kuhl’s desire to perform well at the highest level is having some kind of impact on his mechanics.
The best cure for excess adrenaline, it would seem, is to get additional repetition and build psychological comfort with pitching at the major league level. Kuhl may certainly get more of those opportunities as the season moves into its final months, given potential injury and workload concerns, as well as lingering performance issues with other members of the Pirates’ starting rotation.
I suspect we will revisit both Kuhl and his lack of ground balls this season, as the wave of interesting pitching prospects continues to arrive for the Pirates. For now, we’ll await his start on Sunday afternoon and see if he can avoid the upper portions of the strike zone against the Nationals.