The Bethlehem Police Department was called to the area of Center Street and East Lehigh Street Friday morning for a report of a cyclist lying in the roadway.
The incident happened around 11 a.m.
Police say when they arrived, they discovered an unconscious man with a head injury.
He was taken to the hospital but has been unable to give a statement.
Police are looking for witnesses.
Anyone with information should contact officer Jon Desiderio, a collision reconstructionist, at 610-865-7179.