ST. LOUIS -- Yadier Molina left Monday night's 4-1 Cardinals win over the Reds in the fifth inning with a queasy stomach, crediting a first-inning foul ball from the Reds' Todd Frazier that hit Molina squarely in his facemask as the culprit for his symptoms.

"Nothing about the heat," Molina said on a day when an excessive heat warning was in effect for eastern Missouri. "Just a foul ball. Sometimes when you're a catcher, those foul balls are going to get you, and this one was one of those."

Molina said, "we'll see" with regard to his status for Tuesday's game. Manager Mike Matheny concluded that dehydration and perhaps some over-caution played into the decision to pull Molina before his spot in the order came up in the fifth.

"He was feeling sick, so we just wanted to cover all our bases," said Matheny, a former catcher. "He did take a good shot to the face with the foul tip, and that was on our mind. But when he started feeling sick, we made a move to get him out. He had the [concussion] tests and everything came back perfect."

Molina received an IV, and both he and Matheny described a visit with the team doctor as precautionary.

"After the foul ball, my stomach started feeling bad," Molina said. "I almost threw up, but right now, I feel better."

Molina led off the fourth inning with a double and scored on Kolten Wong's grand slam. Backup catcher Tony Cruz pinch-hit for Molina in the fifth and remained in the game behind the plate.

The Cardinals gave Molina a day off on Sunday. It was his first time out of the starting lineup since he sat for the first game of a doubleheader on July 7.

The 33-year-old has played in 92 of the Cardinals' 99 games and is hitting .291, including his two at-bats in Monday's game.

Molina became just the latest run-producer for the club to be dealing with temporary health issues as outfielders Randal Grichuk (groin) and Matt Holliday (quad) and first baseman Mark Reynolds (hand) were held out of Monday's starting lineup.