N’Golo Kante’s season could be over after he suffered a hamstring injury during Chelsea’s victory against Watford.
The French midfielder went off after 11 minutes of the game at Stamford Bridge, where the Blues won 3-0.
He will be assessed on Monday but the initial signs are that he will miss the Europa League match against Eintracht Frankfurt and the final Premier League game of the season, at Leicester.
Kante might also be a doubt for the Europa League final should Chelsea come through Thursday’s semi-final second leg.
Maurizio Sarri explained: “The problem is his hamstring. We must wait until tomorrow but I think it’s difficult to recover him for the next two matches.
“We want him to play the final so we will try to recover him for that.”
And head coach Sarri admitted he regretted not resting Kante for Chelsea’s final home league match of the campaign.
“I think I made a mistake, because today he probably had to rest,” said the Italian.
“It is difficult to put an important player like Kante on the bench but I have to say I made a mistake.”
Gary Cahill, overlooked by Sarri for most of the season and set to leave club this summer, was given a hero’s reception by the home fans when brought on for the final few minutes.
Sarri said he was unaware of comments made by Cahill this week about feeling sidelined in his final season with the Blues.
“I don’t know the situation, I’m sorry,” Sarri said. “It’s not important for me.
“Cahill, during the season, was really very professional. He played only five, six or seven matches, but he was really very important in the training ground, in the dressing room.
“Today was his last match for Chelsea, so it was important for him to be on the pitch, only for a few minutes but I still think it was really very important for the fans and for him.
“Here, Gary won everything. And so I think he had to say goodbye to the stadium, to the fans, to the club.”