Manager Rafa Benitez was only appointed in March, but is known to have a relegation get-out clause in his contract.
It remains to be seen whether the popular former Liverpool boss will continue at St. James' Park next season, amid reports linking him to the Everton job, among others.
Warnock, therefore, has been tipped as a replacement should Benitez depart, having led Rotherham United to Championship survival by a margin of 10 points.
For all his acclaim, Warnock carries with him a Marmite reputation, and Murphy has suggested that some Magpies supporters might not be too keen on the Yorkshireman's appointment.
"They have to consider the fans’ reaction," Murphy told the Alan Brazil Sports Breakfast show (c. 09:25). "If you have the fans not completely with the appointment from day one - extra pressure.
"If you’ve got the fans on board… so if Newcastle start the Championship next season with Rafa and they lose a couple of games there’s no drama is there?
"If they give it to Neil Warnock and they lose the first couple, all of a sudden you’ve got protests."
Benitez, who began the season at Real Madrid, hasn't managed below the top tier in any country since 1998.