Weaver, who has not played a game for City since last March, will undergo a scan on his knee later this week when it is expected he will be told the injury will keep him sidelined for at least six weeks and so ending his chances of a return to action this season.
"Nicky hurt his knee in training the other day and it will set him back for the rest of the season," City boss Kevin Keegan told the clubs official website
"Like Paulo Wanchope he will have to get his head round keeping fit, keep doing things right and then come back next season, earlier than usual, so that he can catch up on the ground work he has missed."