The Celtics will be without a major piece to start the playoffs this year, with guard Marcus Smart suffering a torn oblique.
The guard suffered a partial avulsion of his left oblique muscle in the third quarter Sunday against the Orlando Magic, the team announced Wednesday. He is expected to resume basketball activities in four to six weeks.
NBA insider Adrian Wojnarowski of ESPN tweeted earlier that Smart could miss the first two rounds of the playoffs.
Smart played in all but two games this season, including 60 starts, contributing 8.9 points, 4 assists, 2.9 rebounds and 1.8 steals per game.
A thumb injury cost Smart the end of the regular season and the start of the playoffs last year, but he was an integral part of Boston's run to the Eastern Conference Finals.