Kumar Rocker's MLB debut: Five things to know about the Rangers right-hander, including unusual path to majors

Although the Texas Rangers aren't going to become Major League Baseball's first repeat World Series champions in more than two decades, they are providing their fans something to look forward to tonight: the debut of right-hander Kumar Rocker .

Rocker, 24, will get the start against the Seattle Mariners . He received the call to The Show after making 10 minor-league appearances this season, including two most recently at Triple-A. In those two starts, he struck out 18 of the 35 batters he faced and held opponents to two runs on four hits and a walk in 10 innings pitched. In other words, Rocker's time at Triple-A was as dominant as it was brief.

To mark the occasion, here are five things to know about Rocker ahead of his debut.

1. Storied career at Vanderbilt

It's no stretch to describe Rocker as one of the most accomplished collegiate pitchers in recent memory. Across 42 appearances at Vanderbilt (39 of them starting assignments), he amassed a 2.89 ERA and a 4.72 strikeout-to-walk ratio. He struck out more than 33% of the batters he faced over that span.

Rocker rose to national prominence back in 2019, when he delivered a 19-strikeout no-hitter against Duke during postseason play. That was just part of a brilliant NCAA tournament run that saw him go 4-0 with a 0.96 ERA as a freshman.

Rocker's sophomore season was derailed by the COVID-19 pandemic. His junior year saw him as a finalist for both the Golden Spikes Award and Dick Howser Trophy, and he was honored as a First Team All-American and All-SEC performer. Predictably, he was selected fairly high in that summer's draft, but controversy lurked around the bend.

2. Originally drafted by Mets

Rocker was selected 10th by the New York Mets in the 2021 draft and the two sides quickly hashed out a tentative agreement worth a $6 million signing bonus. The Mets attempted to lower that number after developing concerns about his elbow based on the results of a physical. The two sides did not reach a new agreement.

Under MLB's rules, the Mets were compensated with the 11th pick in the following year's draft. They used that selection to take Georgia Tech catcher Kevin Parada . Unfortunately for the Mets, Parada has not developed as desired. In Double-A this season, he batted .208/.298/.337 with a 34% strikeout rate. Earlier this summer, an evaluator with a rival front office told CBS Sports they no longer considered Parada a legitimate big-league prospect.

As for Rocker, he elected against returning to Vanderbilt, instead making his professional debut under unexpected circumstances.

3. Redrafted following indy league stint

Indeed, Rocker's first professional appearances came as a member of the Tri-City Valley Cats of the Frontier League. He dominated the substandard competition, tallying a 1.35 ERA and an 8.00 strikeout-to-walk ratio in five tune-up outings before the draft. ( Those appearances were important since they came after he underwent a "minor scope" of his shoulder the previous winter, after not signing with the Mets .)

The Rangers were taken enough by Rocker to select him No. 3 overall in one of the bigger surprises of the first round. It marked the second consecutive draft the Rangers took a Vanderbilt right-hander with a top-three pick; the previous summer, they used the No. 2 selection on Jack Leiter .

Rocker would make his Texas organizational debut in the Arizona Fall League, employing different mechanics than those he used during his collegiate days. Alas, whatever hopes the Rangers had of Rocker and Leiter joining their big-league rotation in short order were derailed the following spring.

4. Injury strikes

Rocker made six starts at High-A to begin the 2023 season before going down with elbow trouble. He required Tommy John surgery in May that not only thwarted his 2023 season, but ensured he would miss most of the 2024 season as well.

Rocker made his return to regular season action on July 5, or just under 14 months from the date of the surgery -- the usual timeline teams provide their pitchers these days.

As noted in the introduction, Rocker made 10 appearances (nine starts) across three minor-league levels, notching a 1.96 ERA and an 11 strikeout-to-walk ratio. He only recently reached Triple-A, where he excelled in two starts and convinced the Rangers he was worth giving a look-see at the big-league level.

5. Has shown electric arsenal in return

It's been more than three years since Rocker last pitched on national television. You might wonder what his arsenal even looks like these days. We have you covered.

According to the ball-tracking data from Rocker's two Triple-A outings, his fastballs (he throws a four-seamer and a sinker) have averaged 97.8 mph and topped out at 99.9 mph. Those pitches play hotter than that thanks to a deep release point achieved by him getting down the mound. His most-used individual pitch is his trademark slider, an 85 mph pitch that generated a 74% whiff rate in those two starts and has received double-plus grades in the past. (That's a fancy way of saying it's nearly elite.)

Rocker also sprinkles in a changeup, though evaluators have typically been lower on that offering.