United's strike pairing of Gary Hooper and Paul Hayes have been linked with moves away from the club this summer, with Hayes out of contract and free to leave for nothing.
Hooper, who finished the season as the club's top scorer, is not out-of-contract and would command a fee should he be sold. Left-back Marcus Williams is also free to leave on a Bosman transfer, having previously made no secret of his desire to move on.
Nigel Adkins, who is expected to announce his retained list towards the end of the week, warned that even with the highest wages ever offered by the club it may not be enough to prevent players leaving.
"There are clubs out there with far greater resources who can give them greater rewards but I know the club has done all it can," he said.
"We need to reward them. The players have achieved in the Championship. We have really pushed the boat out.
"The lads have done the business and they have to do right by themselves. If they leave, they will leave as heroes."
United's players took the applause of supporters on an end-of-season lap of honour, but the Forest side were preparing for a two-legged play-off semi-final against Blackpool.
"We'll go into those games as well prepared as we possibly can be but we haven't played Blackpool in the play-offs before so that bit is new," said David Kelly, Forest's assistant manager.
"They've beaten us twice and they are a good team. It'll be a tough game but hopefully we'll have a bit of luck and get to Wembley."
Should Forest be heading to the national stadium for the play-off final later this month, they will take on either Leicester or Cardiff City.