ST. LOUIS -- Cardinals catcher Yadier Molina wasn't sure how a baseball stuck to his chest protector after a wild pitch by Brett Cecil in the seventh inning, but it wasn't as funny after Kyle Schwarber hit a three-run homer two batters later to propel the Cubs to a 6-4 victory Thursday.

TV close-ups of Molina's chest protector later showed a white, star-shaped smudge low on his chest protector where the ball was stuck a few seconds earlier. Molina took exception when a reporter asked if he puts pine tar or another foreign substance on his gear.

"Do I put anything on my chest protector? No. That's a dumb question," said Molina, who could not locate the ball as it clung to him, which helped set up Chicago's rally.

Catchers sometimes put pine tar somewhere on their uniforms, often around the shin guards, to help give them a better grip. There are no rules against the practice, though it is against the rules for players to have pine tar on their skin, or to place it on the ball. Umpires could have addressed the matter had the Cubs made an issue of it, but that wasn't the case Thursday.

Molina was certain about one thing.

"That play changed everything,'' he said. "If we get that first out, everything changes.''

It allowed Cubs pinch hitter Matt Szczur to reach first base after a swinging third strike to lead off the seventh inning. Molina repeatedly spun around, looking for the ball, and smiled upon seeing where it wound up.

After a walk to Jon Jay, Schwarber homered to right to give the Cubs a 5-4 lead.

"First time in ... how many, 13 years? I don't know how that happened," Molina said. "I didn't feel anything different than any other ball, so I don't know how that happened."

Cecil left the clubhouse without speaking to reporters. The former Toronto pitcher, who signed a four-year, $30.5 million contract with the Cardinals last winter, allowed four runs without recording an out and took the loss in his second game with the team.

Cardinals manager Mike Matheny also said, repeatedly, that he had no idea how the ball stuck to Molina.

"I've never seen that before," Matheny said. "I don't know what happened. That's all I can tell you."

The Cubs did not ask umpire Quinn Wolcott to check the ball. None of them seemed particularly surprised and assumed that Molina was simply using a sticky substance to get a better grip on the ball, given the blustery conditions.

"It was probably Tuf-Skin, sticky spray, something like that, maybe pine tar," said Cubs outfielder Jason Heyward, who used to play for the Cardinals. "Probably Tuf-Skin. I've never seen that happen. We joked about it the next time I came up to the plate. We had a saying when I was over here: 'Never seen it.'

"It definitely came into effect right there. It was hilarious. Guys that aren't pitchers have stuff on all of the time, on their glove, whatever. It is what it is. Catchers have stuff all the time."

Added Cubs manager Joe Maddon: "I don't know if they've come out with Velcro on the protectors or it's just a fuzzy baseball. It was definitely Velcro-ed to his chest.''

Schwarber, who broke into the major leagues as a catcher, also said foreign substances are commonly used by backstops.

"Catchers like to put pine tar on their shin guards and throw balls to second base and get a good feeling," Schwarber said. "Maybe it rubbed off some and it stuck. You never know. That's a pretty crazy theory. I don't know. I put pine tar on my shin guards. It happens."

Information from The Associated Press was used in this report.