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