Jose Mourinho insisted it was too early to speculate on the severity of Harry Kane's latest apparent ankle injury.
The Tottenham striker limped off in added time at the end of Tottenham's 2-2 Premier League draw at Everton, having scored both of his side's goals.
"Me too (I am worried)," Spurs boss Mourinho told Sky Sports. "I think it is too early to say something.
"For him to leave the pitch (at) 2-2, with a couple of minutes to go, it is obviously because he felt something. But let me be optimistic and believe he has time to recover, let's see."
As well as the battle for Champions League qualification, Spurs are in Carabao Cup final action against Manchester City at Wembley a week on Sunday, but Mourinho is trying to remain positive.
He added: "Let me be optimistic and believe it is nothing serious. It is obvious he is a very important player for us, that is more than obvious, but I cannot say much. I cannot speculate or help with any speculation."
Tottenham defender Eric Dier admitted it was worrying to see Kane limp off.
He said: "Obviously it is always worrying when you see him limping because he doesn't fall over easily. He takes a lot of knocks and gets on with it, but it is obviously early days to say what it is or how bad it is.
"He is a tough boy and he will do as good as he can to be ready."
