ESPN.com is reporting that Raiders owner Al Davis has been pushing for Lane Kiffin to resign as his head coach and is considering Dennis Green as a potential replacement, sources close to Kiffin and the team told ESPN's Chris Mortensen. Davis has gone so far to draft a letter of resignation for Kiffin to sign, a source said. Kiffin has refused to do so but has dared Davis to fire him instead. Kiffin, who was 4-12 in his first season as coach, has two years remaining on his contract at an estimated $2 million per year.