Leading wide receiver Pierre Garçon won’t be returning to the 49ers this season because of a neck injury. General manager John Lynch, on KNBR 680-AM, announced Thursday that Garçon was heading to injured reserve, where the winless 49ers (0-8) already have sent 15 other players. Garçon sustained a non-displaced fracture that is not considered career threatening but requires an eight-week recovery. “We had him as questionable because all the imaging we did checked out clean,” Lynch said. “Our medical staff felt something just wasn’t right. They sent him for more testing on Wednesday. “Unfortunately last night we found out he has a non-displaced fracture of the right C5 pedicle. It’s an eight-week injury. They have to immobilize it.” Garçon was halfway to the first 1,000-yard season by a 49ers receiver since Anquan Boldin in 2014. A late-hit out of bounds in Sunday’s 33-10 loss at Philadelphia apparently resulted in Garçon’s injury.