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