Millwall manager Kenny Jackett has admitted it is 'inevitable' that Zak Whitbread will leave the club.
The American centre-back is keen to play in a higher division as he hopes to be included in the USA's squad for next year's World Cup in South Africa.
Peterborough have already had an offer accepted, but the Championship new boys failed to agree personal terms with the defender.
Despite the Lions receiving no other bids for Whitbread this summer, Jackett realises that the 25-year-old's future probably lies away from the New Den.
"We've had no other bids for Zak this summer, apart from the Peterborough bid," the Millwall manager told skysports.com.
"He is a very good player, so if he does end up staying at Millwall then that would be terrific, but at the same time he has stated his wish to leave and that looks inevitable.
"It's difficult when a player shows a desire to be elsewhere and players often get what they want these days, but we'll have to wait and see if anyone else comes in for him."
The Lions have made three summer signings this year, with John Sullivan, Steve Morison and Jason Price all being brought to the club.
Jackett says he is still looking to bring in more new recruits before the end of the transfer window in September.
He added: "If we can get someone in then yes we would like to bring some extra bodies in before the September deadline, but we won't be doing it for the sake of it
"If we find someone that will improve on what we've got here then we will pursue it. If not, then I am more than happy with what I have got here."