Kumar Rocker and Jack Leiter: A Pitching Odyssey

Underwhelmed.


That’s the word I’d use to describe my feelings this weekend after witnessing the starts posted by Vanderbilt pitchers Kumar Rocker and Jack Leiter. It was hard to type that word given all the negative connotations it carries while knowing what type of precocious talents Vanderbilt has in both righthanders. But expectations were high at 7:00 PM on Friday night, and barely 24 hours later, I was left sitting in the press box at Florida Ballpark wondering what could have been.


Rocker hurled 5 innings in the Commodores 11-7 victory over the Florida Gators Friday, striking out 8 hitters but allowing four walks and posting a mediocre 49/46 strike/ball ratio. Just as concerning, the jumbo-sized righty gave up a mammoth home run to Florida slugger Kris Armstrong as well as a plethora of other well-struck balls.

Leiter fared far worse on Saturday. The New Jersey native lasted just 4 innings and exited after yielding three long balls and walking four Gators.


Let’s first examine Rocker’s outing.


When dissecting Kumar Rocker, the first order of business is establishing the lexicon. Rocker throws two breaking pitches—the more “famous” of the two resides at about 80 MPH and occasionally has the standard 12-to-6 curveball break and other times approaches the plate at more of a slant, depending on the position of Rocker’s wrist upon release of the pitch. To the trained eye, this pitch would appear to be a curveball; however, Rocker and the Vanderbilt baseball contingent refer to this pitch as a slider. Hence, this is the terminology I’ll use for the remainder of this article.


Rocker’s other “breaking pitch” travels in the 87-88 MPH range and has a much tighter break. Many would call this pitch a slider, but Rocker & Co. have labelled this offering a cutter. To each his own.


The correct terminology established, let’s delve into Rocker’s start. Because of all the attention Rocker’s three-start dip in fastball velocity (from his customary 93-95 MPH to a more sedate 90-91) garnered, it’s imperative to point out that the big guy had the heat turned on Friday. Most of his fastballs sat in the 93-94 space and some touched 95 and even 96.


Rocker kicked off his outing by fanning Gator leadoff man Jacob Young with some 93 MPH cheddar at the letters. He then hit 95-96 several times to induce a Jud Fabian pop up and whiff Armstrong. Armstrong’s AB was not without drama; however, as the brawny switch hitter hit a nuke off a 94 MPH fastball that was barely foul down the right field line.

Three things quickly became apparent as Rocker battled his way through the Florida lineup. First, the Vanderbilt ace works fast, appearing ready to fire the next pitch immediately after getting the ball back from his catcher. After decades of playing and following this sport, I’ve come to notice that a pitcher who works fast is a confident pitcher and this trait certainly holds true for Rocker. Second, Rocker was repeatedly aided by the home plate umpire’s generous strike zone, particularly on high pitches. This helped him garner several high-fastball strikes. Finally, Rocker pitches with emotion. There was an assortment of F-bombs, fist pumps, and scowls. In short, the kid left it all on the mound Friday.


As his outing progressed, Rocker mainly toggled between his fastball, which stayed true at 93-94 MPH for his entire 5-inning stint, and his slider, and sprinkled in some cutters when necessary. Though Rocker collected a bunch of Ks, his command was off and several Gator hitters took advantage.


Nathan Hickey, Florida’s second-place hitter, drove a 94 MPH center-cut heater to center field in the 1st inning for a line drive single.


Two batters later, as I alluded to above, Rocker grooved a 93 MPH heater to Armstrong, which landed barely foul some 400 feet away.


In the 2nd inning, Kendrick Calilao turned around a Rocker fastball and hit a loud flyout to center field.


In the 4th, Rocker once again left a fastball up to Armstrong and this time Armstrong wasn’t as forgiving, launching a 400+ foot missile that left the bat at 108 MPH.


One batter later, true freshman Sterlin Thompson tagged a 95 MPH waist-high fastball for a loud lineout to right field.


In that same inning, Josh Rivera swatted a Rocker fastball for a screaming one hopper to Vandy SS Carter Young. Young made a great play on the ball but couldn’t throw out Rivera.

If you think you’re seeing a pattern here, it’s because you are. Though Rocker was able to get a number of swinging strikes on his high-octane fastball, it got hit hard when his command of the pitch faltered.


In addition to giving up hard contact when his fastball command was lacking, Rocker’s difficulty controlling the pitch was the primary culprit for the four walks he surrendered. An example of this came in the 5th inning when Rocker walked Fabian on a 3-0 fastball. In this instance, as well as throughout most of the game, when Rocker missed with the fastball it was to his glove side.


As in most of his starts this season, Rocker had more luck with his slider. What makes this pitch so effective, is Rocker’s ability to “tunnel” it with his fastball. This means the ball leaves his hand in nearly the exact same fashion with both pitches, making it nearly impossible for the hitter to discern between the two offerings.


Rocker’s adroitness with the slider induced a number of swings-and-misses and also resulted in multiple called strikes. In the 3rd inning, Jordan Carrion, still reeling from swinging through a high hard one, took a high slider for strike 3. Then Armstrong and Thompson went down back-to-back waving at 80 MPH sliders to end the 5th.


Though Rocker had his moments like the ones featured immediately above, his inconsistent fastball command and control are an important blemish that will have to be ironed out for him to reach his ultimate ceiling of front-of-the-MLB-rotation workhorse.

Let’s now look at Leiter’s outing.

Until his start on April 17, Jack Leiter’s spring had been the season dreams are made of. The 6-01/205 righty had dominated in each of his starts, and notched a 20-inning hitless streak, which, of course, included the 9-inning no-hitter he tossed on March 21 against South Carolina.


Much of Leiter’s early success this season was predicated on his devastating fastball, which has been called the best pitch in the draft by scouts and analysts alike. In his well-thought out article from April 6, Fangraphs’ Justin Choi explains in great detail the keys to Leiter’s fabled heater. In a nutshell, Leiter’s low release height of 5.2 feet combined with his elite 6.6-foot extension, 95% spin efficiency, and 19.9-inch vertical break all combine to make his fastball torturous for collegiate hitters.


However, after never having thrown more than approximately 60 innings in any one spring season, Vandy’s Saturday starter has seemingly hit a wall. He entered this start having given up seven earned runs and five homers in his last two outings after yielding just three of the former and one of the latter in his first eight appearances. I was curious to see if this trend would continue.


Unfortunately, I didn’t have long to wait. Leiter kicked off his act with a series of 94 MPH fastballs to the Gator table setter Young and walked him on five pitches. He then walked Hickey on five pitches. Up to the plate strode Fabian.


As I’ll discuss in a subsequent article, it hasn’t been the kindest of springs for Fabian. The Florida center fielder and three-place hitter entered the season as a possible candidate to go first overall in the upcoming July draft, but a strikeout rate that is parked near 30 percent may force him to fall out of the 1st round altogether. That said, he has a lightning-quick bat and one of the college game’s top average exit velocities. This would be no picnic for Jersey Jack.