The Independent Office for Police Conduct launched an investigation after South Yorkshire police bosses referred the incident to the police watchdog.
A 16-year-old Sheffield Wednesday fan was left bleeding when he was struck over his head with a baton after The Owls played Barnsley at Oakwell last season.
Mobile phone footage of the incident was shared online and showed a police officer striking the boy over his head, leaving him covered in blood.
Police officers were monitoring away fans as they made their way from Barnsley’s ground towards the transport interchange in the town.
The officer involved is still working for South Yorkshire Police but has been placed on restricted duties pending the outcome of the IOPC’s criminal and misconduct investigations.