Marcus Smart will miss 4-6 weeks after being diagnosed with a torn oblique on his left side.
The timeline would sideline Smart through the Celtics' first round matchup against the Pacers, and a potential second round matchup against the Bucks.
Smart will resume basketball activities in 4 weeks.
Smart has been one of the Boston Celtics' most productive players. Jaylen Brown will likely take his place in the lineup.
Smart re-signed with the Celtics last offseason on a four-year, $52 million deal.