ST. LOUIS — The Dodgers took two steps forward and one big step back Saturday with their injury-plagued pitching staff, activating relievers Michael Kopech and Kirby Yates while sidelining starter Tony Gonsolin because of discomfort in his surgically repaired right elbow.

Dodgers manager Dave Roberts said Gonsolin will undergo an MRI scan to determine the extent of the injury.

“With a pitcher, when there’s elbow discomfort, we didn’t see him making his next start. And so it just seemed like the logical thing, given where the pitching is at, to get him offline, give him a handful of days to not play catch,” he said. “Hopefully that discomfort subsides.”