Shane Victorino shifted over from right field Friday night to make his fifth start of the season in center. Victorino also moved into Ellsbury's leadoff spot for the fifth time.
Red Sox manager John Farrell says Ellsbury aggravated his ailing foot when he stole second base in the 10th inning Thursday night. Ellsbury then scored the decisive run, on Victorino's single, in Boston's 9-8 victory.
Ellsbury fouled a pitch off his foot last week against Baltimore, and Farrell says the pain and throbbing increased Thursday night. The manager said Ellsbury would receive treatment Friday and hopefully return to the lineup Saturday.
Ellsbury was batting .299 with eight homers, 52 RBIs and 89 runs. He leads the majors with 52 stolen bases in 56 tries, a 92.9 percent success rate.
Boston began the day with a 6½-game lead in the AL East.