Source: Team_Talk
Whitbread placed on Lions list
The 25-year-old centre-half has a year left on his current deal and has in the past been linked with Everton and Blackburn, as well as a number of Championship clubs.
Millwall do not want to lose American-born Whitbread for nothing next summer and have therefore made him available for transfer.
Lions managing director Andy Ambler said: "Zak has one year left on his current contract but has turned down our offer to discuss a new deal.
"As a result of that, Zak has been placed on the transfer list."