Rzepczynski will give the Cardinals' bullpen three southpaws. The 27-year-old began the season in the Majors and appeared in nine games, allowing seven runs over eight innings, before his demotion on April 29. He posted a 3.07 ERA in 32 relief appearances, spanning 44 innings, with Memphis.
The fifth-year veteran, acquired from Toronto near the 2011 Trade Deadline, appeared in 70 games for the Cardinals last season and was an integral member of the bullpen in 2011, when St. Louis won the World Series. Rzepczynski said his focus in the Minors was returning to his 2011 form.
"I went down there every day and just tried to be the best that I could be," he said. ""I just had to take a step back and start over, and just try to get back to where I can be, and I know I can."
With the departure of Mitchell Boggs via trade to the Rockies and his extended stay in Memphis, Rzepczynski admitted his mind did wander regarding his long-term future with the Cardinals, especially with Wednesday's Trade Deadline approaching.
"Down there, a little bit, I didn't know what was going to happen," he said. "With the guys throwing up here, I didn't know if I was going to be here in September, now, ever again. You just never know with that kind of situation.
"Once you've been traded once, anything is bound to happen. I'm just happy to be here now, help the team win. If something happens, something happens, but right now I'm just happy to be back."
Martinez, the Cardinals' Minor League Pitcher of the Month in June, pitched just 3 1/3 innings after being added to the big league roster on July 11. He struck out two and allowed three runs. He had posted a 1.98 ERA in eight starts with Memphis prior to his callup.
"It just worked out to the point where Carlos really wasn't getting the amount of innings he needed," manager Mike Matheny said. "We needed to go and make sure that he's getting built up and able to improve. He's still a very young pitcher. It was nice to get him in [Wednesday] night to have a good feeling before he went off."