Rangers prospect Kumar Rocker, twice a first-round pick, to make his MLB debut

Texas Rangers right-handed pitching prospect Kumar Rocker will make his major-league debut on Thursday against the Seattle Mariners, the team announced on Monday. The news comes roughly 16 months after he had Tommy John surgery.

On Thursday, we Rock. pic.twitter.com/DmTSivC4Hi

— Texas Rangers (@Rangers) September 9, 2024

Rocker, 24, didn’t debut this season until July 5, as he completed his rehab from the elbow surgery. But he’s been on a fast trajectory ever since then. In 10 appearances (nine starts) across three levels, Rocker had a 1.96 ERA and a 55:5 K:BB in 36 2/3 innings. In his last start for Triple-A Round Rock, he allowed two runs in five innings, striking out eight and walking one.

A star at Vanderbilt, Rocker threw a no-hitter with 19 strikeouts in a Super Regional game against Duke as a freshman. Coming out of the pandemic-shortened 2021 season, Rocker was an early favorite to be the No. 1 pick in the 2021 MLB Draft. However, he struggled at times to show the elite stuff and plus velocity that he had as a freshman. Still, he went with the 10th pick that season to the New York Mets. However, the team elected not to make him a contract offer, as they didn’t like what they saw in his medicals after the draft.

Rather than return to Vanderbilt for his senior season, Rocker had shoulder surgery the following September and then pitched in the MLB Draft League in the weeks leading up to the 2022 MLB Draft. The Rangers surprised everyone on draft day, taking Rocker with the No. 3 pick. He signed a below-slot deal, which allowed the Rangers to give above-slot contracts to later picks in the draft. He got off to a strong start in 2023 but injured his elbow and had surgery in late May.

Coming into the season, Rocker ranked as by The Athletic’s Keith Law as the Rangers’ No. 6 prospect, although that was before he had fully completed his rehab. Rocker’s elite velocity has returned post-surgery. In his last outing on Friday, Rocker’s fastball regularly topped 97 mph and he also featured a low-90s changeup and a mid-80s slider.

Law says Rocker’s arm slot is back to pre-surgery form, allowing his stuff to return to what he had that freshman season at Vanderbilt.

“Before Rocker’s surgery — even before the Rangers drafted him — his arm slot had moved downward, perhaps to reduce any pain or soreness in his shoulder, and it made his slider far less potent or effective than it was when he was at his peak in his freshman year at Vanderbilt,” says Law. “Since his return, he’s been back to a true three-quarters slot, working 95-100 mph, with a grade-70 slider again, while he’s got a hammer 12/6 curveball to go with it.

“In Triple A, hitters swung at his slider 31 times, and they whiffed on 23 of them (74 percent). He’s topped out at 72 pitches in an outing this year, and his last appearance marked the first time he faced any hitter three times in a game, so I don’t expect him to go very deep into any starts in the majors, but this is the stuff he had in high school and before his no-hitter in the College World Series back in 2019.”

Rocker joins a Rangers’ rotation that also currently includes his teammate at Vanderbilt, Jack Leiter, who was the No. 2 pick in the 2021 draft. Rocker is the son of former NFL lineman and current Tennessee Titans defensive line coach Tracy Rocker.