Culpepper, 31, played nine seasons, including last year with the Oakland Raiders. He was not resigned by the Raiders after last season and didn't catch on with another team.
He wrote in an e-mail message said he'd been told if a quarterback was injured in training camp he would be given a chance but "I would rather shut the door to such an 'opportunity' than continue to wait for one of my fellow quarterbacks to suffer a serious injury."
Culpepper was the 11th overall pick in the 1999 draft by the Minnesota Vikings. He was a Pro Bowl selection in 2000, 2003 and 2004. His best season statistically was 2004, when he completed 69.2 percent of his passes for 4,717 yards and 39 touchdowns. He tore three knee ligaments in 2005 and wasn't as effective as he'd been previously.
He was traded to Miami before the 2006 season but appeared in only four games. The Raiders signed him for 2007 and he appeared in seven games last year.