The Englewood Police Dept. says officers were called to the home at 1:17 AM in reference to a man standing outside the residence. While cops were en route, the man entered the home.

According to court records, Kelly sat down on a couch next to the home owner ... as she held her baby. The woman said Kelly was "mumbling incoherently."

Cops say a male inside the house hit Kelly in the upper back with a 2-3 foot stick shaped piece from a vacuum ... and was able to chase him outside.

Officers searched the area and were able to locate Kelly inside of a black SUV.

24-year-old Kelly -- a former star at Ole Miss -- was arrested and charged with 1st-degree criminal trespass, as first reported by Ian Rapoport.

He was transported to a nearby jail where he was booked and later released.

It's not Kelly's first brush with the law -- he was arrested back in 2014 after getting into a fight outside of a nightclub in Buffalo, NY. He later pled guilty to disorderly conduct.

9:55 AM PT -- The Broncos just released a statement on Kelly's arrest, saying ... "We are disappointed that Chad Kelly was arrested early this morning. Our organization has been in contact with Chad, and we are in the process of gathering more information.”