“The communication between the club and fans is terrible,” Shearer wrote in The Sun. “Even the captain Fabricio Coloccini barely says anything.
“After the Leicester defeat it was left to Paul Dummett to front up. The captain should be coming out with a strong message and supporting his manager.”
Newcastle’s poor run of form continued on Saturday afternoon, as they suffered an embarrassing 5-1 defeat to Palace at Selhurst Park in London.
Steve McClaren’s side actually took the lead, but they collapsed thereafter and left much to be desired.
Coloccini started the match and played for the entire 90 minutes, but he was once again a big failure in defence.
The defeat has reinforced the belief among many Premier League followers that Newcastle could get relegated to the Championship at the end of the season.
The Magpies are second from bottom in the league table at the moment with just 10 points from 14 matches.
Newcastle are two points behind 17th-place Sunderland, who have won their last two Premier League matches and appear to be on form at the moment.