Manchester United face an anxious wait over the fitness of Romelu Lukaku after the striker limped off during his side's Premier League victory over Arsenal on Sunday.
The Belgium ace, 24, had to be substituted at the start of the second half at Old Trafford following a challenge from Gunners defender Konstantinos Mavropanos.
Lukaku - United's top scorer with 26 goals so far this season - looked in clear pain as he headed towards the touchline to be replaced by Marcus Rashford.
Speaking after United's win over Arsenal, Mourinho said: "I don't know if he is going to be out.
"Or if he's not okay. He wants to play all the time. He is never tired and, when he has small things, he doesn't care. He still wants to go.
"So, for him to say immediately, to change him, it is because he couldn't play. But there are three more weeks until the final, so let's see. I know it was on his foot but I don't know more yet.
"I don't think it's something, or I hope it's not, that in this moment keeps him immediately out of a game that is in three weeks' time.
“But I don't know. I never, when I finish a game and a player is injured, immediately go for good or bad news. I wait a bit more."
Mourinho's side opened the scoring against Arsenal thanks to Paul Pogba's first-half strike but former United man Henrikh Mkhitaryan levelled the match after the interval.
However, Marouane Fellaini scored a last-gasp winner to earn United all three points and seal their place in next season's Champions League.