"We'll have some more tests to see where we're at," Bochy said. "We do have some concern there. He played last night. We wouldn't have played him if he had symptoms. This just came on. He was playing great."
Giants general manager Bobby Evans said after Tuesday's game that Panik's case will be reviewed by Major League Baseball on Wednesday.
Panik excelled during the Giants' most recent road trip, with three game-winning hits and 10 RBIs while the Giants took six of seven games in Tampa Bay and Pittsburgh. He even hit a home run and tallied four RBIs on the day he was struck in the head.
Ramiro Pena moved to second base and Conor Gillaspie played third in Panik's absence, with Angel Pagan hitting second in the lineup.
Panik would join an already crowded infield on the DL if he does have a concussion -- a group that includes Matt Duffy, Ehire Adrianza and Kelby Tomlinson. Duffy, who was put on the 15-day DL June 20, is recovering from a left Achilles strain and still in a walking boot. Duffy said he hit off a tee Monday and Tuesday.
"He's not doing a lot right now," Bochy said. "He'll be in that boot five more days. It's hard to be encouraged until we get him out of that boot."
Bochy also said Adrianza, who is on the 60-day DL with a fractured left foot, could start his rehab by next week.
• Matt Cain (right hamstring strain) threw a bullpen session Tuesday and will pitch Friday in the Rookie-level Arizona League. Bochy said Cain will make another rehab appearance after that with the goal of him returning to the Giants' rotation after the All-Star break.
Justin Wise is a reporter for MLB.com based in the Bay Area. This story was not subject to the approval of Major League Baseball or its clubs.