Koch, who was recalled from Triple-A Reno on Thursday, missed more than two months earlier this season due to a shoulder impingement, Bill Mitchell of Baseball America reports.
Koch is completely healthy after missing significant time with the injury, and should see his first appearance of the season Thursday against the Reds or during the Diamondbacks' three-game series with the Nationals over the weekend. With Koch taking over Taijuan Walker's spot on the active roster after Walker hit the paternity list, it's possible that Koch could be called upon to make a spot start Saturday against the Nationals if he goes unused over the next two days. Koch wouldn't make for an appealing streaming option in that scenario, as he was sporting a 8.47 ERA in 17 innings at Reno prior to his promotion.