Cardiff City are looking to get Whittingham tied to a new deal. Already Kevin McNaughton has agreed to sign a contract extention.
"We rejected the bid from Nottingham Forest as we want to keep hold of Whittingham," said Cardiff chief executive Gethin Jenkins.
"We are continuing negotiations with Peter over a new contract here at Cardiff City."
The new season kicks off in 4 days but the transfer window is open until the end of the month.