SAN FRANCISCO - The San Francisco Giants placed left fielder Nori Aoki on the seven-day concussion list Thursday, one day after he had to leave the game with symptoms from a head injury sustained against the Cubs last weekend.

He left Sunday's game in Chicago after he was hit in the head by a pitch in the third inning, then returned to the starting lineup Wednesday against Houston but played only five innings before running into the wall to make a catch.

Aoki said Thursday he had nausea and a difficult time focusing that had subsided by Thursday and had no headaches. But manager Bruce Bochy said there were still other symptoms that led to the DL.

"He needs some time," Bochy said.

The move is retroactive to Wednesday. San Francisco recalled outfielder Ryan Lollis from Triple-A Sacramento.