Tatum (illness) has been ruled out for Monday's game against the Magic, Taylor Snow of the Celtics' official site reports.
Tatum was removed from the starting lineup and added to the injury report just minutes before Monday's tipoff due to illness. While he never joined the Celtics' bench, the team waited until halftime to officially rule him out. Al Horford, Sam Hauser and Luke Kornet should continue to see more action while Tatum is unavailable. Tatum's next chance to play will come Wednesday against Philadelphia.