The Boston Celtics are planning to discipline coach Ime Udoka, likely with a suspension, because of an improper relationship with a member of the organization, two people with knowledge of the matter told The Associated Press on Thursday.

The people spoke to the AP on condition of anonymity because the reigning Eastern Conference champions have not revealed any details publicly. The exact punishment, including the length of the possible suspension, has not been determined.

ESPN first reported Wednesday night that a suspension was under consideration for the team policy violation. ESPN and The Athletic later reported that the Celtics’ investigation revolves around whether Udoka had an inappropriate relationship with a member of the organization.

Losing Udoka would be a significant blow to a team that is widely considered among the favorites to contend for an NBA title this season, after falling only two games short of winning the championship last season in his debut year.

The Celtics open training camp on Tuesday. If Udoka will not be allowed to lead the team, the task would almost certainly fall to one of his assistants. A possible candidate, Joe Mazzulla, interviewed for the Utah Jazz coaching job this summer, a position that ultimately went to Will Hardy — who was Udoka’s assistant in Boston last season.

Udoka’s other assistant coaches are Damon Stoudemire, Ben Sullivan, Aaron Miles and Tony Dobbins.

Udoka had a brilliant first season as coach of the Celtics, finishing the regular season at 51-31 — going 26-6 in the final 32 games — and leading Boston past Brooklyn, Milwaukee and Miami on the way to the NBA Finals. The Celtics lost the title series to the Golden State Warriors in six games.