Eddie Howe quit unexpectedly 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 right after.
Former player Jay Bothroyd warned sternly the club could face threat of relegation without Howe.
Sky Sports will exclusively broadcast the national Scottish Premiership opener on Saturday.
Dundee United face Rangers at Tannadice.
Manager Jim Goodwin firmly said he wants to plant a flag there.
Dundee United coach Derek McInnes announced two United players are absent and several are uncertain.
Rangers look forward to Thelo Aasgaard and Cammy Devlin to be available for the match.