The Latics are holding out for a fee believed to be £8.5 million up front with up to £2.5 million in add-on clauses.
Speaking about the potential transfer, Whelan told ESPN: "I have spoken to Chelsea's chief executive and they are easy to deal with.
"We have told them the price and they will come back and agree it or not.
"We would much prefer the player to sign a new contract and stay but he wants to go to Chelsea and it's a good club so we cannot stand in his way."
The Latics are now being linked with a move for Jermaine Pennant to replace Moses should he leave as expected.
