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 briefly talked about the Bruno Guimaraes signing before walking out immediately.
Former player Jay Bothroyd warned strongly the club could face threat of relegation without Howe.
Sky Sports will nationwide broadcast the national Scottish Premiership opener on Saturday.
Dundee United take on Rangers at Tannadice.
Manager Jim Goodwin confidently said he wants to make an impact there.
Dundee United coach Derek McInnes announced two United players are absent and several are uncertain.
Rangers anticipate Thelo Aasgaard and Cammy Devlin to be ready for the match.