Zac Gallen returned to the mound Wednesday night for the first time in more than two months as the Arizona Diamondbacks attempted to complete a series sweep against the Kansas City Royals at Kauffman Stadium.

The right-hander had not pitched since July 7, when Arizona suffered a 4-1 road loss against the San Diego Padres.

Rain delayed the beginning of Wednesday’s game, although the first pitch ultimately came only 50 minutes later than originally scheduled.

Gallen’s return was far from dominant, but he managed to prevent the outing from completely unraveling.

He allowed two runs (one earned) on four hits (one home run) with a strikeout and two walks in 3.1 innings to get a no-decision.

Gallen entered Wednesday with a 6.34 ERA in 98 innings, the worst qualified ERA in MLB when he was injured with right elbow inflammation. His ERA dropped to 6.22 in 101.1 innings. The Diamondbacks ultimately lost 5-2.

There was at least one encouraging development involving his knuckle-curve.

The pitch has traditionally been one of Gallen’s best weapons for finishing hitters, although its effectiveness has declined in recent seasons alongside his broader struggles.

Despite an uneven performance, Gallen commanded the curveball better Wednesday. He generated four called strikes and three whiffs on eight swings.

The sample was small, but it was his most effective pitch of the night.

Expecting Gallen to work beyond five innings after such a lengthy absence was unrealistic.

Although the results were not elite, he provided 3.1 innings while giving up only two runs (one earned).

Arizona trailed 2-1 when he departed, but Gallen at least kept the Diamondbacks within striking distance. 

At this stage, that is something Arizona can take from his return.

The bigger concern remains hard contact, an issue that has followed Gallen throughout this season after also causing problems in 2025.

Wednesday offered little evidence that problem has disappeared.

Six of the 12 balls put in play against him were hit harder than 95 mph, qualifying as hard-hit contact. Five were struck harder than 100 mph.

Royals catcher Carter Jensen produced the biggest blow in the third inning, crushing a 108.6 mph home run 416 feet for Gallen’s only earned run.

Gallen was fortunate that the other four balls hit at least 100 mph resulted in outs.

That is not something he can consistently rely upon.

At his best, Gallen succeeds because of much more than overpowering velocity. His strongest qualities have traditionally been command, sequencing and the ability to make different pitches work together.

The knuckle-curve is particularly important because it gives hitters a dramatically different look and can become a finishing weapon when he locates it properly.

Gallen also has the experience to adjust during an outing rather than allowing one difficult inning to dictate the rest of his night.

His composure has been central to his success throughout his career.

After such a long absence, rebuilding consistency will require more than one start.

Wednesday showed that his curveball can still create uncomfortable at-bats.

It also showed how much work remains if Gallen is going to prevent hitters from consistently squaring him up.