The Good And Not So Good From Zac Gallen's Return from Injury

Right-hander Zac Gallen had not appeared in a game for the Arizona Diamondbacks since July 7. On Wednesday night, with a chance to earn a series sweep against the Kansas City Royals at Kaufmann Stadium in Kansas City.

Despite the game beginning in a rain delay, first pitch took place only 50 minutes later than anticipated.

It was not exactly a brilliant outing from the former ace, though he did manage to avoid total disaster. The 6.34 ERA he held heading into Wednesday's game — which was the worst qualified ERA in the major leagues at the time of his injury — lowered to 6.22 in the process.

Here's the good and the not so good from Gallen's return to the mound:

The good from Zac Gallen's return to Diamondbacks

Arizona Diamondbacks right-hander Zac Gallen (23) pitches against the San Francisco Giants at Chase Field in Phoenix on July 1, 2026. | USA TODAY Network via Reuters Connect

The curveball

Gallen's knuckle-curve has been one of his best knockout pitches for most of his career. It has not quite been as effective in recent seasons, though that is reflective of his wholesale struggles.

Though Gallen's night was a bit bumpy and uneven, he had his curve working better than it had been. He landed four of them for called strikes and collected three whiffs on eight swings. It was a small sample size, but it was the most effective pitch in his arsenal Wednesday.

Relative box score success

Coming back off such a lengthy downtime, it was not realistic to see a five-plus inning start out of Gallen. Though his results were not elite, he was able to provide 3.1 innings of coverage, while only allowing two runs (one unearned).

At the very least, the Diamondbacks, who trailed 2-1 when Gallen exited the game, were given a chance to win a game when their starter left the mound. At this stage, that's all Arizona can ask.

The not so good from Zac Gallen's return to Diamondbacks

May 12, 2026; Arlington, Texas, USA; Arizona Diamondbacks pitcher Zac Gallen (23) waits in the dugout during the first inning against the Texas Rangers at Globe Life Field. Mandatory Credit: Andrew Dieb-Imagn Images | IMAGN IMAGES via Reuters Connect

His (lack of) fastball usage

Gallen's four-seam fastball has been the hinge point of his issues for multiple seasons. It simply has not been an effective pitch since the early stages of 2024.

Unfortunately, that was the case again Wednesday. Gallen shied away from his fastball after the third one he threw was hit 106.5 MPH (albeit for an out). He threw only nine out of 68 total pitches, tied with his sinker for the least-used offering on the night.

The fastball's velocity was also significantly down. This is not a major concern after a lengthy IL stint and an elbow injury. But Gallen's four-seam averaged 91.2 MPH, which is 2.2 MPH down from his 93.4 yearly average.

It's not concerning in the context of his injury, but it does make an already-ineffective pitch that much tougher to utilize.

Hard contact, again

Gallen has struggled with hard contact all season, a continuation of 2025's issues. That did not appear to have dampened to any degree on Wednesday.

Out of 12 batted balls in play, six were hit harder than 95 MPH (considered "hard-hit") worse than that, five were hammered harder than 100 MPH.

He allowed a 108.6 MPH home run smashed 416 feet deep to Royals catcher Carter Jensen for his lone earned run, but was lucky to see his other four 100-plus MPH batted balls go for outs. That luck will not last long in this game.

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