Claudio Ranieri has demanded that Eric Abidal explain why he left Monaco's stadium ahead of Sunday's 1-1 draw with Lille.
The defender, who has been out of action for a month, had been left out of the starting XI as the principality club lost further ground on leaders Paris Saint-Germain in the race for the Ligue 1 title.
Ranieri explained after the game that the former Barcelona full-back had departed the Stade Louis II without permission, hinting that his departure was in reaction to not being selected to return from injury.
"It's his problem, I know he was at home," Ranieri told reporters. "He did not stay for the game.
"If there is a problem I will talk with the club. I want to know why he left. He was not on the bench. He left.
"He had a good week and trained every day but I preferred another player."
Monaco meet Lens in the Coupe de France quarter-finals on Wednesday and Ranieri is open to reconciliation should the 34-year-old perform well behind the scenes in midweek, despite his disobedience on Sunday.
"I will see how Abidal goes in the training session and I will then make a decision," he added.
Monaco now sit 10 points adrift of PSG at the summit of Ligue 1 with eight games left to play.