D.C. Metropolitan Police Department spokesman Paul Metcalf confirmed to NFL Media on Monday that Morgan was arrested early Sunday morning and booked on one charge of misdemeanor simple assault.
Morgan was released after his booking. The Washington Post reported his court date is May 22.
The wide receiver told WRC-TV that he's innocent of any wrongdoing.
"I didn't touch him," Morgan said Monday. "I didn't do anything. This is crazy. I'm not worried about nothing.
"I have always been a stand-up guy in the community. Nothing like this has ever happened to me before."
Morgan, 28, signed a one-year deal with the Bears last week after spending the last two seasons with the Washington Redskins. In 14 games (seven starts) last season, Morgan had 20 receptions for 214 yards. He was held without a touchdown catch for the first time in his six-year career.