Diamondbacks Prospect Mitch Bratt's Numbers Are Hard to Believe

The Diamondbacks' No. 14 prospect is doing something extremely rare.

Feb 18, 2026; Scottsdale, AZ, USA; Arizona Diamondbacks pitcher Mitch Bratt (60) poses for a photo for MLB media day at Salt River Fields at Talking Stick. Mandatory Credit: Allan Henry-Imagn Images | Allan Henry-Imagn Images

The Arizona Diamondbacks are getting close to a point where they may be forced to take a long look at the output of one of their top pitching prospects.

Left-handed starter Mitch Bratt — who was part of the return in the trade that sent Merrill Kelly to the Texas Rangers at the 2025 deadline — isn't just pitching well. He's dominating an offense-heavy environment to nearly an unprecedented level.

It's starting to become difficult to believe the numbers he's putting up week in and week out, and he's only 22 years old at the Triple-A level. Let's take a look at them:

Diamondbacks' prospect Mitch Bratt dominating AAA

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, in his most recent start for the Aces, completed an excellent start. He pitched five innings without allowing an earned run, while striking out five, allowing just three base hits and avoiding walks entirely.

That effort lowered his full-season ERA to 2.35. That ERA is second in the Pacific Coast League among starting pitchers with at least 30 innings logged.

Granted, Bratt's Fielding Independent Pitching (FIP) is somewhat higher, at 3.94, but that number is also an extremely above-average figure for such an offensive league. Pitchers with ERAs and peripherals well north of 4.00 and even into the 5.00s can still be considered "good" in that environment.

For context, the PCL's league-wide average ERA is 5.47. The Reno Aces' cumulative team ERA is 5.10, which ranks fourth. The Tacoma Rainiers (Seattle), have the best team ERA in the PCL, at 4.34. It's also worth noting Bratt is nearly six years younger than the average PCL pitcher (27.8).

Are Bratt's numbers full-season sustainable? Perhaps not. A blowup outing is only ever a few swings away in the PCL. But what's been encouraging about Bratt is his ability to prevent base traffic in general. That allows for the occasional home run or extra-base knock to hurt much less than it might have with juiced bases.

Bratt has issued 10 walks in 38.1 innings (nine starts). He has not walked more than one batter in an outing since April 25, and has walked only one batter in May — his past four starts. He's struck out 21 in 19.2 May innings, with a 1.86 ERA in the process. Barring a blowup start in his next outing, he will be a very strong candidate for PCL Pitcher of the Month.

Bratt's stuff is, admittedly, not the most electric. His fastball averages just over 90 MPH with little movement, but he is a left-hander with a relatively deep arsenal, and a curveball that could develop into a weapon.

He'll likely need to display perfect command to survive at the major league level, or find a way to add either a couple ticks of velocity or a bit more bite to his stuff. But there is something to be said for getting the job done at such a tough level while not relying on stuff alone.

Meanwhile, the Diamondbacks' major league rotation has performed surprisingly well of late, and Bratt is still a bit young to force Arizona's hand into a call-up, but it's going to be impossible to ignore him for much longer if he keeps this pace up in such pitcher-unfriendly league.