A former skipper at the northeast club, Shearer was stunned by Saturday's 3-2 defeat to Swansea at St James' Park which was the Magpies' seventh straight loss, their worst ever run in the top flight.
That loss left them 14th with 35 points, just five ahead of arch-rivals Sunderland in 18th with four games to go.
“Have no doubts about it - Newcastle are now in real danger of going down,” Shearer wrote in his column in The Sun.
“I didn't think so until Saturday but after that performance I can't actually say with any certainty that we will get another point this season.”
The 44-year-old lays the blame firmly on the players, lamenting their attitude and expressed sympathy for head coach John Carver as he tries to get more from them.
He added: “Carver himself has been getting some stick. But he loves the club and I know he is hurting.
“Why don't the Newcastle players start taking some responsibility? Because right now they are an embarrassment.”
Newcastle have won just twice in 16 matches since Carver replaced Alan Pardew as manager.
Shearer has been impressed by Aston Villa's resurgence, Leicester's remarkable four-game winning streak and feels Hull will be buoyed by their win over Palace at the weekend.
He feels all those sides can overhaul Newcastle and just questioned if Sunderland can get the points they need to drag Newcastle deeper into the mire. – AFP
Original source: Shearer fears relegation for Magpies