It’s possible Udoka could be sidelined for the entire season for the “consensual, intimate relationship,” according to the sports network.
The Athletic independently confirmed the report through sources, who said the relationship was a “violation of organizational policy.”
Udoka’s job is likely not in permanent peril, according to ESPN.
In his first year as head coach last season, Udoka guided the Celtics to the NBA Finals for the first time in 12 years.
A video of Udoka’s girlfriend, actor Nia Long, dancing after the team advanced to the championship went viral.
The Celtics lost to the Golden State Warriors in six games in the NBA Finals.
The team didn’t immediately reply to HuffPost’s request for comment.