Millen -- who was the Lions' president and general manager when he was fired Sept. 24, 2008 -- was a guest studio panelist for NBC Sports before Saturday's Indianapolis-San Diego AFC wild-card playoff contest.
When he was fired by Lions' Chairman William Clay Ford, Detroit was 0-3, and later became the first NFL team to finish a season 0-16.
"I would have (fired himself), actually," Millen said, responding to a question by NBC's Dan Patrick. "Probably not this year until after the season. I think when you start having changeover in an organization it filters down into the locker room."
Millen, 50, played on four Super Bowl-winning teams during a 12-year NFL career, but had no player personnel experience when he was hired by the Lions in 2001.