Molina was sent for medical tests for a knee injury and did not play Saturday against the Marlins, but before leaving he told teammates he didn't believe it was anything serious.
Pitcher Adam Wainwright said Molina told him he'd probably be OK with a little rest and that the tests were "purely precautionary." Molina has been among the best players in the league the first half of the season.
"It's been bothering him a little bit, I think," Wainwright said. "What he told me is it's not something a couple days won't heal him up. I think he's going to be just fine."
Manager Mike Matheny said the knee began bothering Molina on Friday night.
"We saw some things during the game that gave us an indication," Matheny said. "So we're going to have to wait and see what the medical staff says."
Molina has played in 81 of St. Louis' 86 games and leads the National League with a .346 average. He has six homers and 45 RBIs. Backup Tony Cruz made his eighth start of the season and first since June 26.
Wainwright was named to his second All-Star team, though he won't be able to pitch. The Cardinals adjusted their rotation to give the 11-game winner two more starts before the break, and he'll work the final game before the break next Sunday.
"I'm perfectly OK with that," Wainwright said. "I know the rules. They just said I can't pitch, they never said I couldn't pinch hit."
Wainwright said a chance to help the Cardinals make the postseason trumped an opportunity to pitch an inning or two in the All-Star Game.
"Would I rather have two more starts and try to help the team win two more games or pitch the seventh inning?" Wainwright said. "I'm taking the two games every time."