Boss Martin Ling told BBC Radio Cambridgeshire: "We've had a bid from a Blue Square Premier side that is now under consideration by the board."
Willmott's contract is set to expire at the end of the season.
But the U's would be entitled to a fee should Willmott leave the club in the summer, as long as they offer him a new deal.
"Robbie Willmott might not be with us at the weekend, he might be with us at the weekend," added Ling. "It's over to the board.
"It's out of my hands. I've done all of the negotiations with the other club and I've moved it over to the board."
Interest in Willmott and fellow Cambridge youth product Josh Coulson has been high since the club was put up for sale in January.
Meanwhile, general manager Robert Smith and club secretary Lisa Baldwin have both resigned their positions.
The U's say that while the reasons have been "personal" they have been "triggered, at least in part, by the situation in and around the club".
A statement added: "We reassure supporters that the key operations of the club will remain unaffected."
Source: BBC Sport