The 1999 season would turn out to be Young's last in the NFL. Young was plagued by concussions throughout his career. During a Week 3 "Monday Night Football" game against the Arizona Cardinals, Young was violently sacked by Cardinals cornerback Aeneas Williams on a blitz. Running back Lawrence Phillips was supposed to pick up Williams, but missed. Young was knocked out of the game with a concussion, and didn't return again for the rest of the season due to symptoms of post-concussion syndrome. The concussion he suffered against the Cardinals was reportedly his second in a season that was only three weeks old, and the seventh (at least) of his career. Following the season, the 49ers told him that he would be released if he did not retire. Although Young was offered a job as the starting quarterback of the Denver Broncos (where his former offensive coordinator, Mike Shanahan, was the head coach), he retired because of his repeated concussions. In a 2013 "Frontline" interview, Young said that, partially based upon their own experiences, he and many retired players are increasingly concerned about repeated concussions and subconcussive hits. He is particularly concerned about certain positions that take frequent hits, such as running backs and linemen.