Corbin Burnes' Worst Start as a Diamondback Comes at Brutal Time

There was no delusion that returning ace Corbin Burnes would look as sharp as he did prior to his injury in his first handful of starts following Tommy John surgery. Unfortunately, the Arizona Diamondbacks do not have much room to play with as the season grows long.

On Monday night against the Miami Marlins, Burnes had his shakiest start as a member of the Diamondbacks. Granted, it was only his 13th in an Arizona uniform, but it was not a pretty one.

Corbin Burnes has rough start vs Marlins

Sep 8, 2026; Kansas City, Missouri, USA; Arizona Diamondbacks starting pitcher Corbin Burnes (39) delivers a pitch against the Kansas City Royals during the first inning at Kauffman Stadium. Mandatory Credit: Denny Medley-Imagn Images | IMAGN IMAGES via Reuters Connect

Burnes allowed five base hits in just 4.1 innings of work, needing an even 75 pitches (which was, essentially, his upward limit) to do so.

He allowed five earned runs, partially due to a pair of two-out solo home runs in the top of the fourth inning. He struck out four batters, and was able to pick up a decent amount of swing-and-miss, and did not issue a walk. The five earned runs allowed were the most Burnes has coughed up in a start with Arizona.

Burnes' changeup was working. He picked up five whiffs on five swings with that offering. His curveball collected five more whiffs on 12 swings, though it was also responsible for the first of his two homers allowed.

However, Burnes' command still appeared to be lacking; plenty of pitches sailed arm-side. The velocity of his trademark cutter and sinker remained in the 93 MPH region. After a mostly successful 3.1-inning scoreless return debut, this was not the result Burnes nor the Diamondbacks might have hoped for.

Neither of those realities lies far outside what might have been expected.

His return from both elbow surgery and a shoulder injury was going to cost him plenty of time to ramp back up to full strength, even once he return to a major league mound.

Corbin Burnes' outing not concerning, but not insignificant

Sep 14, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Corbin Burnes (39) throws in the first inning against the Miami Marlins at Chase Field. Mandatory Credit: Matt Kartozian-Imagn Images | IMAGN IMAGES via Reuters Connect

When Burnes exited, the Diamondbacks found themselves staring down a 5-3 deficit — certainly not the largest gap Arizona has faced this season, but a poor position to win a game, to be sure.

The actual results from Burnes are nothing to overreact to. It would be a near-impossibility to see him return to full form this season. If he returns in 2027 to similar issues, there would be a larger cause for concern.

For now, however, the Diamondbacks are running out of time to allow their ace to work out the rust for an extended period.

Not only has Arizona struggled to provide enough runs to back up repeatedly poor starts, their plus bullpen has had to labor through a season of relatively inconsistent starting pitching.

If starts like Monday's happen in the rest of Burnes' outings, the D-backs may be in danger of surrendering necessary Wild Card ground. As it is, the San Diego Padres came into Monday's game with a 2.5-game lead for the final Wild Card berth. They then beat the Rockies 8-7 on Monday night.

Arizona's chances at a postseason run have thinned out enough, already. They don't have much time to allow Burnes to dial it back up.

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