PARK RIDGE, Ill. (AP) — Doctors say they are hopeful a player for a Chicago-area junior hockey team who suffered a spinal cord injury during a game last month will recover from his injuries.

Matt Olson lost his balance and slammed into boards last month while playing for the Chicago Cougars. The 20-year-old, a native of Isanti, Minnesota, couldn’t move his arms or legs following the mishap. Doctors were optimistic Tuesday After Olson underwent surgery and experimental treatments.

Dr. John Ruge said Olson was of clear mind after surgery and suffered no head injury. He added doctors initially believed Olson’s spinal cord was severed, but determined it was “severely pinched.”

Ruge said adult stem cells found “among the hockey community” were infused in Olson to assist in the recovery of the spinal column. Ruge says it’s too early to determine his prognosis.