Wellemeyer, trying to come back from soreness in his right (pitching) elbow, has made one start since June 5. He threw fastballs and breaking balls in his Saturday mound session, which lasted about 40 pitches. Wellemeyer will throw another, lighter, bullpen on Tuesday.
"Everything felt pretty good," he said. "My slider felt back to normal. I was getting out over it. Felt great."
Officially, the Cardinals have yet to announce a starting pitcher beyond Sunday's series finale at Fenway Park, when Joel Pineiro will toe the rubber. Unofficially, Braden Looper will get the call on Tuesday in Detroit, and Kyle Lohse is almost certain to pitch Wednesday against the Tigers.
Wellemeyer could slot in on Thursday. But if he's not cleared, or if the club simply wants to give him an extra day, Mitchell Boggs could take a game in Detroit with Wellemeyer going Friday in Kansas City or later than that.
"[Wellemeyer] said he felt really good," manager Tony La Russa said. "So I think he's under consideration for a Detroit start, or if not, for sure Kansas City. That's good news."
Mark Mulder could still figure in the equation before the club's current three-city road trip is out. Mulder almost certainly will not pitch in Detroit, but he has not been ruled out for Kansas City.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.