Lowry initially suffered the injury during Game 3 of Miami's quarterfinal series against the Atlanta Hawks on April 22. He missed four straight games before returning for Game 3 against the Sixers on Friday night. He reinjured the hamstring during the first half of Game 4 before missing Game 5 on Tuesday night.
Heat coach Erik Spoelstra said before Game 5 that Lowry did not require another MRI on the hamstring and was day-to-day.
Gabe Vincent, who started in Lowry's absence in Game 5, is expected to start once again. He finished with 15 points, five rebounds and two assists in 28 minutes in Tuesday's win over Philadelphia.
Tipoff for Game 6 between the Heat and 76ers is set for 7 p.m. ET on ESPN.