Michael Wacha will re-examined Monday to determine the level of healing in his right shoulder.
Wacha has been on the disabled list with a stress reaction in the shoulder since June 18. The injury, which settled in the St. Louis Cardinals pitcher's scapula, is a precursor to a more serious stress fracture.
The Cardinals are hopeful Wacha's injury was diagnosed, and is being treated, before it could become a greater issue.
"We'll start comparing those MRIs and those first tests I took a couple of weeks ago," said Wacha, who hasn't thrown and remains in mostly rest mode. "I'm doing a bunch of shoulder exercises and I've got this bone-healing ultrasound stuff I've been using. (And) I've been taking some calcium, Vitamin D stuff. Hopefully, it's been working."
Wacha said the injury largely remains a mystery.
"I had never really heard of an injury like this," he said. "I think it's a new experience for not only myself, but for our training staff. But it definitely feels a lot stronger. It's not as tight as it was. ... It was never pain. It was just tightness back there, just kind of pulling. It took longer to warm up."
Wacha recently called Arizona Diamondbacks pitcher Brandon McCarthy, who has suffered stress reactions and stress fractures in his shoulder. McCarthy also endured a skull fracture in 2012 when he was struck by a line drive.
"He said all he needed was rest," Wacha said, referring to McCarthy's experience with the stress reaction. "He said he has something like 14 days of not throwing and it was basically out of there, and he started up his throwing program again. I feel like (I've) been going through the same stages that he was going through."
Wacha last pitched June 17, a six-inning outing in a 5-2 victory over the New York Mets at Busch Stadium.
Reliever Kevin Siegrist (strained left forearm) could begin a minor-league rehab before the homestand ends Thursday.
"He had two real good days of long-toss and is feeling better," Cardinals manager Mike Matheny said. "Everything seems to be moving more in a positive direction as of late."
Right-hander Joe Kelly (strained left hamstring) has made two rehab starts for Class AAA Memphis and Matheny said he will take two more before being re-evaluated.
"Kelly felt real good after that last start (Tuesday)," Matheny said. "He's going to get a couple more and we'll see him after the (All-Star) break and see how everything feels and where we line up."
Second baseman Kolten Wong (bruised left shoulder) will be eligible to return from the disabled list Sunday. But the Cardinals haven't determined when he will be activated.
"He's doing a nice job and everything seems to be feeling good as far as health goes," Matheny said. "He's also doing a nice job with getting his swing and his defense in time."
Left-hander Jaime Garcia (shoulder inflammation) said he didn't have time to talk Friday when approached by reporters, but said he would address them soon.
Rosters for the July 15 All-Star game at Target Field in Minnesota will be revealed at 6 p.m. Sunday. Matheny will manage the National League team; Boston's John Farrell will manage the American League squad.
Once again, fans have selected the starters --eight players in the NL, nine players in the American League, including a designated hitter.
Major-league players, coaches and managers have selected 16 players per roster --five starting pitchers, three relievers and a backup player at all eight positions.
That left Matheny to choose nine more players for the NL roster, one of which will be a designated hitter. Every NL and AL team must have at least one All-Star.
The fans will select one final player to the NL and AL teams in voting conducted on the Internet beginning Monday.
The Cardinals' Yadier Molina was leading the fan voting at catcher, and starting pitcher Adam Wainwright is a shoo-in to be named to the team. Cardinals reliever Pat Neshek could make his first All-Star team, based on a first half in which he is 2-0 with an 0.82 ERA in 38 games.
With the Marlins in town, Matheny was asked Friday about whether Giancarlo Stanton would be his choice at DH, since Stanton won't finish among the top three outfielders.
"They're all under consideration," Matheny said, avoiding the question. "All of them are under the same possibility at this point. (Stanton) has had a great year. I think everybody understands and appreciates the job he's done."
Stanton is batting .309 with 21 homers and 62 RBIs.
Matheny said the All-Star game remains "fan-driven," which begs the question: Should home-field advantage in the World Series depend on the outcome of the game?
"I like it meaning something," Matheny said. "I think everybody else who manages this game goes in with the anticipation, 'It could affect our October.' That's the way we're going to go about it.
"It did seem more like an exhibition before. ... I know guys have a lot of pride, too. So even an exhibition, they're all out there for the world to see their talents. They're not going to half-step."