Tottenham are hoping that Dele Alli is not the latest attacking player they will lose to injury or being unavailable.
The England international came off during Sunday's last-gasp 2-1 win at Fulham with a hamstring injury and boss Mauricio Pochettino admitted that it did "not look great".
Alli had earlier scored an equaliser at Craven Cottage after Fernando Llorente's own goal put Fulham in front and he watched from the bench as Harry Winks headed a winner deep into time added on.
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.
Pochettino said: "You know very well the action. 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."
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."