PITTSBURGH -- The Cardinals shuffled their bullpen mix Tuesday by activating right-handed reliever Mike Mayers from the 60-day injured list and designating left-handed reliever Chasen Shreve for assignment.

Mayers was placed on the injured list with a strained left lat muscle in April. He had allowed five runs in 8 1/3 innings before the injury, and he appeared in 10 Triple-A games during June and July while rehabbing with Memphis.

The club needed to decide Mayers' roster status by Friday at the latest, and it decided to make the move before then given that the bullpen had been recently taxed, working 11 2/3 innings over the past two days.

“It was really a timing issue,” manager Mike Shildt said. “We were going to deal with [Mike] in the next couple of days anyway, and just realized that we need to make sure that we had as fresh an arm as possible.”

Shreve earned the win in Monday’s 6-5, 10-inning win over the Pirates after recording a strikeout of Bryan Reynolds to send the game to extras before being charged with two runs. His three appearances on the season, across which he’s allowed just the two runs in two innings, have all come in a six-day span leading up to Monday’s game.

The left-hander holds a 3.78 ERA over 23 games in his two seasons with the Cardinals.

“He was a guy that’s pitched kind of recently, and we feel like that was the move for now, so we’ll see what happens,” Shildt said. “We want what’s best for Chasen, honestly -- whatever is best for him and his career -- but we’ll see what happens.”

Shildt said he knows the “domino effect” bullpen usage can have on options and who is available to come up or go down at any time, but the importance of winning has to be the first priority in that decision-making process.

“The options are the options,” he said. “Last night was about getting it done. Every night is about getting it done.”

With the move, St. Louis has two left-handers available in the bullpen in Andrew Miller and Tyler Webb to face the lefty- and switch-hitter-heavy Pirates.

Worth noting
• Matt Carpenter (right foot contusion) officially began his rehab assignment with Triple-A Memphis on Tuesday. He went 0-for-2 with a walk and a run scored in the Redbirds’ 6-4 win over New Orleans. The third baseman has been on the injured list since July 16, and the team is hopeful he can return on Friday, when he is eligible.

• Paul Goldschmidt’s grand slam on Monday was momentous, but it was also historic. The ball bounced into the Allegheny River behind PNC Park, marking the first time a right-handed batter had hit a ball into the river in a game.