Kumar Rocker’s Two-Pitch Approach

The argument could be made that the most intriguing regular season affiliated debut in 2023 occurred when Kumar Rocker, the thrice drafted, two-time top 10 selection toed the rubber for the Rangers’ High-A affiliate in early April. Rocker, of course, captivated the collegiate world with a stellar three-year career atop Vanderbilt’s vaunted rotation, leaving the school with a 2.89 ERA and more than 320 punch outs in only 236.2 innings of work.

Throughout his junior campaign for the Commodores, it was debated whether Rocker or his teammate Jack Leiter would go atop the first round. Leiter ultimate went with the second overall pick, earning the draft class’s highest bonus, and Rocker, the well-built, broad-shouldered right-hander, would tumble to the tenth overall selection. But the Mets – perhaps famously or infamously – found something in his post-draft physical and failed to come to terms with the Georgia-born hurler.

Shortly after Rocker’s agent, Scott Boras, went on record and stated that, “Kumar requires no medical attention and will continue to pitch in the regular course as he prepares to begin his professional career.” Roughly a month later he quietly underwent the knife for some type of shoulder repair, according to MLB.com’s Jim Callis.

Boras had his prized right-hander take the Luke Hochevar route and head to Indy Ball to showcase his talents before the 2022 draft. It worked. The Rangers, who drafted his former ace teammate, grabbed Rocker with the third overall pick last July. He wouldn’t make his professional debut until after the regular season with the Surprise Saguaros in the Arizona Fall League, throwing 14.0 innings with 18 punch outs and whopper of a walk total (12).

Through his first five starts this season, it’s been a different story.

The 6-foot-5, 245-pound righty owns a sparkling 2.70 ERA (with an impeccable 1.49 FIP and a 2.17 xFIP) over 23.1 innings of work, averaging more than 14 punch outs and just 2.31 walks every nine innings.

Unfortunately, though, only one of his starts – an April 29^th contest against the Winston-Salem Dash – was actually televised via MLB.TV. I watched every one of Rocker’s 71 pitches and came away with more questions than answers.

The former Vanderbilt superstar cruised through the first four innings before hitting some speed bumps in his fifth and final frame. His fastball looked good, sitting in the mid-90s and showing two distinct shapes between the four- and two-seamer. And his curveball looked crisp, generating 12 swings-and-miss and four called strikes out of the 28 total times he threw it.

The problem(s), though, are simple: that’s basically all he worked with the entire game. Of the 71 total pitches, he didn’t mix in a changeup (as far as I could discern) and his slider was basically non-existent as well. Everyone – and I mean everyone – in the baseball world raved about Rocker’s slider heading into the 2021 draft.

I called the late-tilting breaker “arguably the best offspeed pitch in the entire class” and graded it as a firm 70. MLB.com called it a “wipeout pitch” and also graded it a 70 as well. CBS Sports referred to it as “one of the draft’s best chase pitches.” FanGraphs noted that it was a plus pitch.

It’s awesome.

But he only threw it four times (as far as I could tell) during his final April game. And here’s the kicker: his backstop that game, Cooper Johnson, only flashed the three-finger slider sign a few times throughout the game. It looked as though there was a plan in place to not throw anything but his fastball and curveball.

Here are the results:

He struggled with his command bit, throwing more non-pitcher strikes than quality strikes. A lot of the called strikes with the heater have more of steal-a-strike approach than anything else. But the work the plus curveball did is undeniable.

Heading into the draft last summer Rocker was already battling some “he’s headed for relief” type remarks. If he’s only throwing two pitches, such as his April 29^th start, that won’t help dispel any of those notions either. But, hey, it’s worked out pretty well for Spencer Strider so far too.