The experienced centre-halves have already been unavailable for a couple of weeks as summer signing Wilson has been struggling with a back problem and Collins has ankle ligament damage.
Wilson's only appearance since mid-September came against Bournemouth on October 19 while the 1-1 draw with the Cherries at the City Ground was the last time Collins featured for the Reds.
And Forest boss Billy Davies has confirmed the pair both face an extended spell on the sidelines.
"Kelvin Wilson will have an operation on his back on Monday which will keep him out for the best part of 10 or 12 weeks and Danny Collins has his ligament damage which will keep him out for around 10 weeks," said Davies following Saturday's home defeat to Blackpool.
The loss saw the Reds suffer successive league defeats for the first time this season and extended their winless run to three matches, leaving Davies' side with just two victories from the last eight Sky Bet Championship games.
However, the Scot said: "There are little things that are not working in our favour but we do not look for any favours, we don't expect pity. We accept that we are in a business where there are highs and lows.
"I am pleased to be in the top six. There are lots of teams who would be pleased to be where we are. Things are going against us. That just the way football is."