Alberto Callaspo replaced Moss at first base in the ninth inning.
"I just rolled it, and when I rolled it my feet came out from under me," Moss said after the game, which the A's won, 1-0, in 12 innings. "Then I tried to get up to run to first, and when I stood up to run it still hurt."
Moss was initially concerned that the injury could be serious, but the pain quickly subsided.
"When I first did it, I thought I had done something to it pretty bad, but when I walked on it, it didn't hurt nearly as bad as I thought it was going to," Moss said.
Moss and manager Bob Melvin said that they will wait to see how the ankle responds Saturday to determine whether Moss will need to miss any time.
Aaron Leibowitz is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.