Gallen (hamstring) is the projected starter for next Tuesday's game against the Reds.

Diamondbacks manager Torey Lovullo said Wednesday that Gallen (hamstring) won't start Friday as scheduled in an effort to provide him extra rest, Alex Weiner of ArizonaSports.com reports.

Gallen (hamstring) expressed optimism Saturday that he will make his next scheduled start, Steve Gilbert of MLB.com reports.

Gallen (3-1) was saddled with a loss Saturday in San Francisco, yielding five runs on nine hits and one walk over five frames. He struck out six.

Gallen (3-0) threw six shutout innings in a win over the Cardinals on Sunday, allowing four hits and two walks while striking out seven.

Gallen threw a career-high tying 40 curveballs in Monday's loss to Colorado, Steve Gilbert of MLB.com reports.

Gallen (1-0) earned the win over Colorado on Thursday, allowing one run on three hits and two walks while striking out three batters over five innings.

Gallen allowed five runs (four earned) on eight hits and three walks while striking out three over four innings in Saturday's spring start against the Guardians.

The Diamondbacks on Monday named Gallen the starter for Opening Day, Damon Allred of Arizona Sports reports.

Gallen is scheduled to throw a simulated game Friday, Steve Stockmar of MLB.com reports.