Irving, who has dealt with several injuries during his brief NBA career, sprained his shoulder Sunday night in a loss to Toronto. He collided with Raptors rookie forward Jonas Valanciunas while trying to drive the baseline. Irving stayed in the game, but was taken out after he was unable to raise his left arm while shooting free throws.
The Cavaliers said an MRI revealed a left AC (acromioclavicular) sprain. He is projected to miss 3 to 4 weeks, but the Cavs have just 19 games left this season, so it's possible Irving will not play again.
Cavs coach Byron Scott would not speculate if Irving's season is over.
"We'll have to wait until it's completely healed and then just go from there,'' Scott said after Monday's practice.
Irving has already missed 14 games this season with a broken index finger and hyperextended knee. He broke his right hand last summer when he punched a padded wall during a practice in Las Vegas. He missed 14 games last season - four with a concussion and 10 with a sprained right shoulder - when he was chosen the league's top rookie.
Irving played with a broken jaw earlier this season, wearing a protective mask.
Despite the injuries, Scott doesn't believe his young star is fragile.
"He's still very young and his body hasn't fully developed,'' Scott said. "I'm just not that concerned about it, to be honest with you,'' Scott said. "All the injuries that he has gotten have been legitimate injuries. It's not something that keeps recurring over and over again.''
Irving played just 11 games as a freshman at Duke because of a toe injury.