Tottenham manager Mauricio Pochettino is concerned about the hamstring injury Dele Alli picked up in his side's last-gasp win at Fulham.
Alli, who cancelled out a Fernando Llorente own goal with a header early in the second half, limped out of the game in the final few minutes, clutching his hamstring.
He watched on from the bench as Harry Winks earned Spurs a vital three points with a header deep into time added on at Craven Cottage, but his problem cast a shadow over Tottenham's victory.
Another injury to an attacking player is the last thing Pochettino needs, given the absence of the injured Harry Kane and Son Heung-min, who is on international duty, over the next few weeks.
It looks highly unlikely that England international Alli, who has already been out twice this season with hamstring problems, will be fit to face Chelsea in the Carabao Cup semi-final second leg at Stamford Bridge on Thursday.
"You know very well the action," Pochettino said. "We need to assess him in the next few days.
"The hamstring is a muscle we need to be careful with, but it doesn't look great.
"On the pitch, we all agree that when you see him put his hands on his hamstring you feel...it's not great."
Alli's likely absence is at least off-set by the potential return of Lucas Moura, who has been working at the club's training ground following a knee injury.
"We're going to go there expecting to win. Like I told you with Kane, and now with Alli, we hope it's not a big issue," Pochettino added.
"We hope Lucas Moura, who was training today at the training ground, is going to be OK.
"Today we didn't want to take a risk with him, but he's nearly 100 per cent. Maybe it's not going to be Dele Alli, but we can have Lucas Moura on the bench or starting at Chelsea."
Fernando Llorente was handed the responsibility of replacing Kane at Craven Cottage, although it is not an afternoon he will remember fondly.
His own goal after 17 minutes put Fulham ahead and then he missed two gilt-edged chances to find the net at the right end, the second a header from close range.
Pochettino was still impressed with what was just the Spaniard's second Premier League start for the club.
"I'm very happy. He fought over 90 minutes, he added his characteristic and quality," said the Spurs boss.
"He had a few chances to score, he was a little bit unlucky. He's now tired after 90 minutes in Premier League, but that's normal."
Fulham manager Claudio Ranieri was concerned by his side's lack of experience after losing the game at the death.
The Cottagers sent a free-kick into the Spurs penalty area in the final stages of time added on, which the visitors cleared and then went up the other end and scored.
The Italian praised his side's performance, but was exasperated by that decision.
"Unbelievable," he said. "Our first half was fantastic and we also had a penalty the referee didn't see. There was a big penalty on (Aleksandar) Mitrovic.
"Second half we controlled the match very well in different ways. We gave a gift with the first goal and the second goal is unbelievable.
"We have a lot of free-kicks and I said to players, 'Why do we have to put the ball in the box?'
"We lack experience. Calm, stay calm, keep possession, finish the match.
"We are alive, we continue to fight, the team showed fantastic performance. I can only say well done. But stay smart until the end. A lot of them the first time they play in the Premier League."