Manager Mike Matheny made the announcement on Sunday, one day after Carpenter threw 95 pitches in his fourth simulated game since returning from July thoracic outlet surgery. Once Carpenter reported no unusual soreness the day after the session, the Cardinals felt confident in making the return official.
"I'm looking forward to it," Carpenter said. "We've worked hard to get back and be able to do this. Like we've said all along, we weren't expecting it, but I'm excited. I think it's going to be a lot of fun. I'm looking forward to getting back out there and competing."
Carpenter's season had been declared over in early July, when it was announced that he would be undergoing a procedure to address a nerve-related issue in his neck/shoulder. At the time, it marked the second instance in which Carpenter had been shut down this year. He had to stop throwing in March due to the same problem.
Now, by starting on Friday, Carpenter will be in line to make as many as three starts before the end of the regular season.
"He's a presence on this team," Matheny said. "He's a leader on this team. We're excited for him. We're excited for us. I'm anxious to watch him pitch."
The Cardinals also clarified the rest of their rotation order. Kyle Lohse will stay on turn and pitch Tuesday's series opener against the Astros. Lance Lynn -- not Joe Kelly -- will follow him on Wednesday. Lynn, who made a spot start for an injured Jake Westbrook last Thursday, earned the chance for another with his performance.
Lynn allowed one earned run on five hits and two walks in six innings against the Dodgers. He struck out seven in the 2-1 win.
Taking advantage of the flexibility afforded by Monday's off-day, Jaime Garcia will slot in Thursday. That allows Garcia to pitch at home, where he has a 2.63 ERA this year.
With the pitching set for next week, Kelly is the odd man out, meaning that he will return to the bullpen. Kelly made two August appearances as a reliever before taking Lynn's spot in the rotation when Lynn began to scuffle. In his start on Friday, Kelly surrendered three runs on four hits and two walks in five innings.