The left-handed pitcher went for X-rays, but the results have not been made public as of Sunday morning.
Red Sox manager John Farrell told the Boston Herald that the injury is believed to be to the top of the foot, and it is not an Achilles injury.
On a night in which not much went right for the Red Sox, Miller injured the foot dodging a line drive, after which he stumbled and turned his foot awkwardly while trying to back up home plate.
Miller, 28, has an ERA of 2.64 in 30⅔ innings for the Red Sox this year. The once-promising starting pitching prospect has become one of the better relievers in the Red Sox bullpen.