ST. PETERSBURG -- Dioner Navarro had to leave Saturday night's A's-Rays game in the top of the seventh inning after taking a ball off his catcher's mask.

During the A's 7-2 win over the Rays, Oakland designated hitter Jack Cust swung at a pitch from Tampa Bay reliever Grant Balfour and fouled the ball into Navarro's mask, causing a blow to his right jaw. The catcher went to his knees and was attended to by manager Joe Maddon and the Rays' medical staff. After several minutes, Navarro walked off the field and was replaced by Michel Hernandez.

"Navvy is at the hospital. He's going to undergo some testing, we're not exactly sure what it is yet, but we'll know more tomorrow, maybe tonight," Maddon said.

Initially, Maddon said Navarro seemed "lucid."

"He just got to the point where he wasn't feeling very good, so we had to get him out of there," Maddon said. "We're just not sure what's going on right now. He was woozy when he left, and he was not feeling well. Of course, our medical people did a great job."

Decisions facing the Rays include whether Navarro is banged up enough to go on the disabled list, which would dictate that he be out of service for at least 15 days. If he is placed on the DL, it's likely Triple-A Durham catcher John Jaso would be called up.

If they don't feel Navarro's injury is serious enough to keep him from returning to play after the All-Star break, the Rays could risk having just one catcher available for Sunday's finale vs. Oakland. Hernandez would be that catcher, with infielder Joe Dillon serving as the emergency backup.

Navarro is hitting .223 with five home runs and 25 RBIs this season.