The England captain suffered a tear in the 1-0 defeat at Southampton on New Year’s Day, although the club have not said what grade it is.
Mourinho again avoided the question, but did reveal his assertion that it is not a minor injury has proven to be correct.
Kane missed the 1-1 FA Cup draw at Middlesbrough and is set to be out for a lengthy period of time, and Mourinho revealed his injury “is not small”, as well as making some classic excuses as his side face a replay.
Mourinho said: “I think it is better for the medical department to speak about it or make an official report.
“The only thing that I can add is that the feelings I had that it was not a small injury were correct.
“It is not a small injury, but I cannot speak about (recovery) times.”
Such is Kane’s importance to Spurs, they do not have an out-and-out replacement and will rely on Son Heung-min and Lucas Moura to fill the void.
Mourinho does not want to dwell on Kane’s absence and says he will come up with an alternative way of playing.
“In this moment it is not going to be, ‘Harry, Harry, Harry, Harry’,” the Portuguese said.
“We have what we have and we stick with them. The boys did what they can, you cannot transform Lucas or Son into a number nine like Harry Kane.
“So we have to try other things and that is what we are going to do.
“Harry is out, obviously every minute he doesn’t play means a lot to us, it is a big loss for us but we have to accept it and we have to fight with the boys that are available.”