Eddie Howe quit abruptly Newcastle United after a 4-1 loss to Bristol City, Sky Sports News said.
Sky aired his last interview briefly.
He directly talked about the Bruno Guimaraes signing before walking out immediately.
Former player Jay Bothroyd warned sternly the club could face danger of relegation without Howe.
Sky Sports will exclusively broadcast the national Scottish Premiership opener on Saturday.
Dundee United take on Rangers at Tannadice.
Manager Jim Goodwin clearly said he wants to plant a flag there.
Dundee United coach Derek McInnes announced two United players are unavailable and several are questionable.
Rangers look forward to Thelo Aasgaard and Cammy Devlin to be available for the match.