Ragnow closed the door on a potential NFL return Friday, Eric Woodyard of ESPN.com reports.
Ragnow attempted to come out of retirement with the Lions last November, but that quest was cut short by a failed physical due to a Grade 3 hamstring strain he'd suffered just days before arriving at the team facility. Ragnow garnered four Pro Bowl selections and three second-team All-Pro honors during a decorated seven-year career.