A photo, posted to the website theChive.com, appears to show a Cleveland police officer holding a "beer bong" and assisting a young tailgater.
WKYC-TV has confirmed that the officer in the photo is a Cleveland police officer and identified him as patrolman Carl Dooley.
Police and union officials have told the station that the officer appears to have used poor judgment.
A police spokesman, Sgt. Ali Pillow, said he was a "bit shocked" to see the picture.
Cleveland Police Patrolmen's Association President Jeff Follmer says, "Sometimes, officers try to fit into their work environment, meaning no harm or diminishing the esteem of the police department."
Pillow said that if the picture is what it appears to be, Dooley may face issues of conduct unbecoming an officer.
Dooley is a field training officer who helps guide new officers learning on the job.
Police said that they were looking into whether the photo was taken during last week's Cleveland Browns preseason game against the St. Louis Rams. WKYC has not confirmed when the photo was taken.