Giants manager Bruce Bochy confirmed the news to members of the media after the game. He said the Giants likely will put Sanchez on the concussion list Saturday and add a player to the roster.
Sanchez struck out in the bottom of the inning before Buster Posey moved from first to catcher to begin the fourth. He was hitting .196 with three home runs and 28 RBIs in 66 games this season.
The Associated Press contributed to this report.