Carpenter's mound session on Friday was his first since throwing approximately 50 pitches during three simulated innings on Tuesday. The right-hander, who is intent on pitching before the end of the season, has not had a setback since resuming a throwing program in mid-August.
Assuming his arm continues to respond well, Carpenter will likely throw between 60-70 pitches in Monday's simulated game. That will be the first of two simulated games Carpenter is scheduled to throw during the team's upcoming seven-game road trip.
The Cardinals have been wary of publicizing Carpenter's timeline with too many specifics because of the number of setbacks Carpenter has already endured this season. He was shut down from throwing during Spring Training and then again in June. That second setback led to Carpenter's decision to undergo thoracic outlet surgery in mid-July.
"I've been bullish about not throwing expectations on him," manager Mike Matheny said. "To say he's got to be here or there ... I don't think it's fair to him."
As it is, though, it's still not out of the realm of possibilities that Carpenter could make as many as three regular-season starts for St. Louis.