DiPietro was injured during warmups Wednesday night before the Islanders faced the Toronto Maple Leafs. He lasted only one period of New York's 4-3 overtime victory.
He underwent an MRI on Thursday and stayed in New York for treatment instead of joining the team in Ottawa for a game that night.
The Islanders said the 26-year-old DiPietro is day-to-day and might play Saturday at home against New Jersey. Now in the second season of a landmark 15-year contract, DiPietro sat out for just the third time in 36 games.
DiPietro allowed two goals on nine shots and earned his third assist of the season during the first period against the Leafs when the Islanders took a 3-2 lead. He didn't return after the intermission.
Wade Dubielewicz stopped 22-of-23 shots and improved to 2-2 on the season. He was expected to start in goal against Ottawa on Thursday night. Joey McDonald was recalled from AHL Bridgeport to serve as the backup goalie.