The seven-day disabled list is limited to players with concussion symptoms. Grandal was hit in the head twice while catching in Friday's game, on the side of the head on a back swing in the third inning and on the mask by a foul ball in the fourth inning. Grandal left after the fourth inning.
Barnes, 25, will make his major league debut when he first appears for the Dodgers, though veteran A.J. Ellis was in the starting lineup Saturday.
Barnes was one of three depth players acquired from the Miami Marlins in the trade for second baseman Dee Gordon and pitcher Dan Haren. The other two, reliever Chris Hatcher and utility man Enrique Hernandez, also are on the Dodgers' major league roster.
Barnes batted .290 with three home runs and a .390 on-base percentage in 29 games at triple-A Oklahoma City. He has 14 walks and 13 strikeouts this season, and he has struck out just once in his last 50 plate appearances.