James left Thursday's win over the Thunder in the fourth quarter after taking a blow to the nose from OKC's Serge Ibaka while making a spectacular slam.
The four-time league MVP remained on the floor for several minutes before being helped to the locker room.
The team said whether James plays in Sunday's home contest against Chicago will be a game-time decision.
The injury came after the Heat superstar had compiled 33 points on 15-of-22 shooting in just 33 minutes against the Thunder.
The Heat won the road game 103-81.