Dan Marino says he inadvertently became a plaintiff in a concussion lawsuit against the NFL and is withdrawing immediately.
The Hall of Fame quarterback said he doesn't suffer any effects from head injuries.
"Within the last year, I authorized a claim to be filed on my behalf, just in case I needed future medical coverage to protect me and my family in the event I later suffered from the effects of head trauma," Marino said in a statement Tuesday.
"I did not realize I would be automatically listed as a plaintiff ... I have made the decision it is not necessary for me to be part of any claims or this lawsuit and, therefore, I am withdrawing as a plaintiff."
Marino's withdrawal costs the litigants a high-profile plaintiff.
He was, by far, the best-known of 15 former players who filed a lawsuit in federal court in Philadelphia last week.
They joined more than 4,800 others who allege the NFL misled players about the long-term dangers of concussions. The league has denied those allegations.
"I am sympathetic to other players who are seeking relief who may have suffered head injuries," Marino said in his statement.
The NFL and the original group of players agreed on a $765-million US settlement last August, but that deal was rejected by a federal judge in January.
Marino, 52, spent his entire 17-year career with the Miami Dolphins and retired as the most prolific passer in NFL history.
He worked as an analyst for CBS from 2002 to 2013, but wasn't retained for this season.
He has had recent discussions with the Dolphins about a role in their front office and a lawsuit might have complicated such a hiring.