Boston Celtics coach Ime Udoka is facing disciplinary action that is expected to include a significant suspension for an unspecified violation of organizational guidelines, sources told ESPN on Wednesday night.

The Celtics are expected to come to a decision on the length of that suspension as soon as Thursday, but it isn't believed that Udoka's job is in jeopardy, sources said.

Udoka's top assistant coach, Will Hardy, left to become coach of the Utah Jazz, and another Jazz finalist, Celtics assistant Joe Mazzulla, would likely be in serious consideration for an interim role, sources told ESPN.

Udoka joined the Celtics last summer after spending time with the San Antonio Spurs, Philadelphia 76ers and Brooklyn Nets as an assistant coach following his NBA playing career.

Udoka replaced Brad Stevens as coach. Stevens moved upstairs to be Boston's president of basketball operations after his predecessor in that job, Danny Ainge, chose to leave the organization.

In his first season as coach, Udoka oversaw a remarkable turnaround in Boston, one that saw the Celtics go from being under .500 in late January to closing the season with a 28-7 record over their final 35 games. They then authored an impressive run through the Eastern Conference playoffs, advancing to the NBA Finals for the first time in 12 years.

Udoka is the fifth coach in the past 25 years to reach the NBA Finals in his first season as a head coach, and the first since Nick Nurse in 2019.

He also, according to ESPN Stats & Information research, became the first rookie coach to win multiple Game 7s in his first postseason. Udoka led Boston to victories over the Milwaukee Bucks in the Eastern Conference semifinals and the Miami Heat in the East finals in seven games before Boston lost to the Golden State Warriors in six games in the NBA Finals.

ESPN NBA writer Tim Bontemps contributed to this report.