Barton, 37, is alleged to have pushed the German at Oakwell on April 13, leaving him with a damaged tooth.
The ex-England midfielder pleaded not guilty to a charge of assault occasioning actual bodily harm when he appeared at Sheffield Crown Court on November 6.
A provisional trial date was fixed for June 1, 2020.
Barton, of Fox Bank Close, in Widnes, Cheshire, stood in the glass-fronted dock, flanked by a security officer, for the 15-minute appearance.
He spoke to confirm his name and date of birth, that he is a UK national, and that he understood various matters outlined by the judge.
Former Barnsley duo left looking for new jobsBarnsley caretaker Adam Murray has steadied the ship - here’s what he can do to land the job permanentlyWearing a dark blue jacket over an open-necked light blue shirt and sporting glasses, he also spoke to enter his not guilty plea to the single charge.
The ex-Manchester City, Newcastle and Burnley player was charged following an incident in the tunnel after the match between Barnsley and Fleetwood, which ended in a 4-2 victory for the home team.
Barton was given unconditional bail by Judge Jeremy Richardson QC.