ST. LOUIS -- Left-hander Tyler Lyons returned to St. Louis after his visit to a specialist, and Aledmys Díaz returned following some downtime in Florida, though neither could provide a confident estimate of when they might return from the disabled list.
Lyons' status is most in question after he received little new information from his meeting with a Chicago-area doctor. Lyons has been diagnosed with a right knee fracture and will rest for at least another three weeks before his status is re-evaluated. He received a platelet-rich plasma injection on Monday.
"I definitely feel like his season may be in question," general manager John Mozeliak said.
"I'm going to be optimistic until they tell me otherwise," Lyons added. "Until there is either no time left or they tell me I'm gone, I plan on pitching again."
Diaz rejoined the team with his right thumb still in a splint. The rookie shortstop fractured that thumb when he was hit by an Andrew Cashner pitch on July 31. He has spent the time since working out at the Cardinals' Jupiter, Fla., complex and welcoming a baby boy into his family.

Diaz has been prioritzing strength work to keep his lower body ready and expects to incorporate more running into his workouts next week. He'll visit a hand specialist on Monday for an update on how his thumb is healing.
"Injuries are part of baseball," Diaz said. "Right now, I just have to ready myself for when I can come back and help my team."
Diaz and Lyons are among a group of rehabbing Cardinals trying to get healthy in time to contribute again this season. Reliever Jordan Walden threw another side session at Busch Stadium on Tuesday and is expected to soon return to Texas to continue his rehab work there.
Walden, who has been out with a right shoulder strain since the end of Spring Training, has said he hopes to join the Cardinals in September. The organization has more cautious expectations and would need him to be healthy enough to go out on a Minor League rehab assignment before considering him ready to return.
"I still think it's something that if he pitches, it will be more of a surprise than expected," Mozeliak said. "The clock is ticking, for sure."
By moving Brayan Peña to the 60-day disabled list on Tuesday, the veteran catcher won't be eligible to return until Sept. 5. Mozeliak said he's "still hopeful" that Pena, who is rehabbing in Jupiter, will return.
One week has passed since Trevor Rosenthal received a platelet-rich plasma injection to address inflammation in his right shoulder, but he has not yet resumed throwing. Rosenthal noted in a recent interview with FOX Sports Midwest that he is also dealing with a significant forearm strain. The Cardinals have not confirmed that diagnosis.
Mozeliak said he will discuss things with Rosenthal before announcing a course of action for the righty reliever.