Manchester United have "initiated appropriate steps" after Cristiano Ronaldo's explosive television interview cast doubt on his future at Old Trafford.
The Premier League club issued an update on Friday to confirm steps are under way, but they did not specify what action they were taking.
Ronaldo, 37, roundly criticised the club when he spoke to broadcaster Piers Morgan.
The Portugal star took aim at manager Erik ten Hag, United's ownership under the Glazer family, and several other members of the club's hierarchy.
United's statement read: "Manchester United has this morning initiated appropriate steps in response to Cristiano Ronaldo’s recent media interview.
"We will not be making further comment until this process reaches its conclusion."
There has been speculation United could terminate the contract of the five-time Ballon d'Or winner, who returned for a second spell with the Red Devils in August of last year.
Ronaldo's former United team-mate Gary Neville has urged the club to get rid of the former Real Madrid and Juventus forward, who is away with Portugal and preparing for the World Cup. Portugal were leaving Lisbon on Friday for their Qatar mission.
"l don't think he wants a way back," Neville told Sky Sports. "He wouldn't have done this interview if he wanted a way back. He knew it would bring the headlines it has and be the end of his Manchester United career.
"I'm wondering what Man Utd are doing because the reality of it is they know they have to terminate Cristiano's contract or they basically open up a precedent so any player can criticise them in the future."
Ronaldo top-scored for United with 24 goals in all competitions last term, but he reportedly asked to leave the club following their failure to qualify for the Champions League.
He has fallen out of favour since Ten Hag took charge ahead of this campaign, regularly featuring as a substitute in the Premier League, and refusing to come off the bench in a game against Tottenham in October.
Ronaldo said in the TalkTV interview: "I feel betrayed. I felt that some people didn't want me here not only this year, but last year too."