"I still have the mindset and desire to play," Leinart said about taking the position behind Palmer with the Oakland Raiders instead of signing where he could compete for a starting job.
"I am obviously still competitive and I hate to be on the sideline sitting and watching ... I know what I can do," he added.
"We have remained close over the years," Leinart said. "He is a guy I have always looked up to, and it's awesome 10 years later to be reunited."
"Coming off the injury, it was a bummer because when I got my shot I was feeling good and playing well, it was such an unlucky break," Leinart said.
Drafted by the Arizona Cardinals in 2006 to be their franchise quarterback, Leinart struggled, eventually surrendering the starting job to Kurt Warner.