Des Plaines Police Chief Jim Prandini told ABC 7 that Daniel Rago, 52, of Mount Prospect has been charged with misdemeanor battery.
Police say the incident happened Friday night around 10:40 p.m. at the Rivers Casino. Hester was in line for a transaction at the cashier's desk inside the casino when Rago allegedly came up behind Hester and slapped him on the back of the head with his open right hand.
"At this time we have no indication there was a previous problem," Prandini said. "There was no brawl or fight between Mr. Hester and the offender in the immediate aftermath. He was just taken into custody and the complaint filed."
Casino security took Rago into custody and Hester signed a complaint against him.
Attempts to get a comment from Rago were unsuccessful.
Hester, holder of the NFL record for return touchdowns, scored two touchdowns Sunday night against the Minnesota Vikings.