Gravesen battling for Celtic stay
But John Sivebaek told the Sunday Express: "Thomas wants to prove that he can be a success at Celtic."
Sivebaek said the midfielder had no intention of leaving Celtic Park and was looking forward to next season.
"I think Thomas will still be at Celtic next season. He will fight to get back into the team," Sivebaek said.
"That is the way he wants to act as a professional footballer. I still think he is a really good footballer and I do not know why he has not been playing at Celtic."
Sivebaek added: "Thomas has never expressed a desire to leave Celtic. He is very happy at the club and very happy with the fans."