"The bullpen could use some help," Matheny said. "Kind of thought that may happen with Jamie. He just needs a little time to get some more tests done and just get to the issue and figure out what's going on."
The Cardinals brought up Salas from Triple-A Memphis before Thursday's game against the Astros and was available to pitch. Salas was optioned to Triple-A on May 26. With Memphis, Salas was 1-0 with a save, giving up four runs and six hits in four innings. He also struck out five.
"He'll be used," Matheny said. "We're excited to get him back."
The bullpen has been especially stretched in the first two games of the series with the Astros. Garcia only went two innings on Tuesday, forcing Maikel Cleto, Sam Freeman, Victor Marte and Mitchell Boggs to get the final 18 outs.
On Wednesday, Adam Wainwright went 5 2/3 innings, but the Cardinals used five relievers -- Marte, Eduardo Sanchez, Marc Rzepczynski, Boggs and Jason Motte -- to finish off the victory.
Other than Salas, any reliever that comes in Thursday's game will have pitched on either Tuesday or Wednesday. Marte and Boggs pitched in both.
Matheny didn't want to say who might fill Garcia's spot in the rotation on Sunday. When asked if he thought the Cardinals would need to make a roster move before Sunday, Matheny suggested that the spot may be filled with somebody already on the roster.
"We've got some ideas, but right now, we'll just go with the extra pitcher in the [bullpen] and figure that out as we get closer," Matheny said.