The Scotland international entered his not guilty plea to the amended charge on Thursday during an appearance at Nottingham Magistrates' Court.
He previously faced one count of common assault.
The charge alleges the 26-year-old striker assaulted Forest fan George Brinkley by beating on 17 May at the City Ground in Nottingham, after the Blades' defeat on penalties.
Wearing a white shirt and a black tie, McBurnie spoke only to confirm his name, address, date of birth and his not guilty plea during a short hearing.
He was told he will stand trial in December.
Sheffield United said it was "disappointed" to learn McBurnie had been summonsed to court, following the conclusion of an inquiry into a pitch invasion after the game by Nottinghamshire Police.
The allegation relates to the club's Sky Bet Championship play-off semi-final second-leg match.
The home side won the match 3-2 on penalties after the tie ended 3-3 on aggregate.
Home fans then invaded the pitch, during which Blades skipper Billy Sharp was headbutted by a supporter who was later jailed.
Forest season ticket holder Robert Biggs, 30, admitted assault occasioning actual bodily harm which left Sharp requiring four stitches to a wound to his lip.
Biggs, a £55,000-a-year electrical engineer, was jailed on May 19 for 24 weeks and handed a 10-year football banning order.
Prosecutors dropped a common assault charge brought against the defendant's teammate Rhian Brewster last week, after a fan claimed he was stamped on during the pitch invasion.
Granting McBurnie unconditional bail, chairman of the bench of magistrates
Geoffrey Evans told the defendant: "You have pleaded not guilty to this offence.
"It will now go to trial here at Nottingham Magistrates' Court.
"We will be granting you unconditional bail.
"If you commit an offence between now and that date that will be treated more seriously because you are on court bail."
McBurnie, of Knaresborough, North Yorkshire, will stand trial at the same court on 7 December.