ST. LOUIS -- St. Louis Cardinals ace Chris Carpenter played catch up to 120 feet Monday for the first time since going on the 15-day disabled list April 15 with a pulled muscle on his left side. Carpenter hoped to throw off a mound as early as this weekend, although he said he still felt some discomfort.
Carpenter said his arm felt strong.
"I'm excited all the time about getting back and feeling better," Carpenter said. "It didn't feel like I haven't thrown in 2½ weeks. It felt good."
The moves came before St. Louis opened a two-game series against the Philadelphia Phillies on Monday night.
Cardinals manager Tony La Russa said he'll continue to go with a 13-man pitching staff for the foreseeable future, given that the Cardinals are in a stretch of 20 games without a day off, although Sunday's game at Washington was postponed by rain.
"If you played for a month, you'd need the extra pitcher more than you'd need the guy on the bench," La Russa said. "It may burn us, but that's just the way it is.
"You can't have everything and we want to preserve our relievers."
Thompson was 0-1 with a 6.75 ERA in four games over 6 2/3 innings before being demoted April 15. He earned the call-up after going 2-0 at Memphis with a 3.45 ERA in three starts with nine strikeouts and one walk in 15 2/3 innings.
He'll go back to the bullpen with the Cardinals.
"He's ready to help us, and it's better for P.J. to go out there and keep developing," La Russa said.
Walters has a 9.58 ERA in five games, including one start in place of Carpenter, while allowing three home runs in 10 1/3 innings.
Information from The Associated Press contributed to this report.