Carpenter, who is recovering from shoulder soreness, picked up the pace with his throwing session on Friday, and he reported no problems. But Carpenter said he'll know more on Sunday, when he plans to throw with additional intensity.
Carpenter threw about 50 pitches after a long-toss session, and he mixed in some breaking balls. Although he picked up the pace from a couple of toss sessions on flat ground earlier in the week, Carpenter said he did not get up to 100 percent.
"It's a progression of intensity and volume," Carpenter said. "We'll do it again on Sunday, and if everything goes well, I'm sure they'll probably have me do something on Tuesday or Wednesday. I've got to get to 100 percent a couple of times before they make that call [to return to action], I assume."
Carpenter experienced shoulder soreness during his start against the Cubs on Aug. 10. The right-hander said his bullpen session on Sunday "will probably be like getting ready for a game."
If Carpenter is able to return to the rotation for the September stretch run, the Cardinals will be able to make a definitive decision on Adam Wainwright's role. Wainwright was the starter on Friday, but the Cardinals have the option of possibly moving Wainwright into the closer role if they get Carpenter back.
Robert Falkoff is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.