Mitch Bratt Won't Wait to Make his Exciting Diamondbacks Debut

The Arizona Diamondbacks are wasting no time in giving the ball to yet another one of their young, rising prospects.

Left-hander Mitch Bratt, who is the Diamondbacks' No. 14 overall prospect and No. 6 pitching prospect, will make his major league debut for Arizona against the St. Louis Cardinals on Wednesday.

On Tuesday, manager Torey Lovullo confirmed to AZCentral's Nick Piecoro that Bratt would be the Diamondbacks' scheduled starter for their game three matchup in St. Louis, after news broke that the left-hander had joined Arizona's taxi squad and would be called up from Triple-A Reno.

Mitch Bratt will start for the Diamondbacks tomorrow, Torey Lovullo said.
— Nick Piecoro (@nickpiecoro) June 24, 2026

The Diamondbacks and Cardinals are in tied at 1-1 in a critical four-game series between two National League playoff hopefuls — though St. Louis is much more firmly in control of their postseason future than Arizona at the current stage.

But with an injury-riddled group of starting pitchers, the Diamondbacks will once again turn to one of their young arms, in hopes of re-establishing some rotational stability.

Diamondbacks' Mitch Bratt to make rapid MLB debut

Mar 13, 2023; Phoenix, Arizona, USA; Canada pitcher Mitch Bratt reacts after being pulled from the game in the first inning against USA during the World Baseball Classic at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | Mark J. Rebilas-Imagn Images

Bratt, 22, will likely be limited in his pitch count on Wednesday, given the fact he just returned from the minor league Injured List with a minor shoulder issue.

He pitched just four innings for Triple-A Reno in his most recent start, so there is a good chance Bratt could be followed by a lengthy relief outing by fellow rookie call-up Kohl Drake, who was part of the same trade to Arizona that sent right-hander Merrill Kelly to the Texas Rangers.

In terms of tangible success this season, Bratt has had plenty. He's got a 2.84 ERA in the high-octane Pacific Coast League environment, which is above average by an extremely wide margin. He's been the most productive starter prospect in Arizona's system this year — at least, among prospects who had a shot at an MLB debut in 2026.

Bratt has gotten it done without high velocity or mind-bending stuff, though his arsenal could play up once out of the Reno elevation. Still, his four-seam fastball is a low-90s offering at best, and he relies more so on location and arsenal variety to achieve results.

The Diamondbacks need any answer they can find for their rotation. Michael Soroka, who was one of the D-backs' strongest arms, is on the IL with a glute injury, and could be out 4-6 weeks.

Ryne Nelson has an elbow strain that will see him shut down for a similar timeline, and that's before he'll even have a chance to ramp back up. The D-backs got a high-quality debut from right-handed rookie Jose Cabrera on Sunday, who tossed five scoreless, confident innings, but they'll need another effort like that from Bratt on Wednesday if they hope to win a big series on the road.

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