The Magpies are currently 17th in the table, just three points above the drop zone.
Crouch believes that the toxicity around the club, along with the lack of confidence and major injuries, could take them down to the Championship.
The popular pundit also claims that Newcastle are better off playing behind closed doors because of discontent among the fans.
The fans are clearly unhappy with the job Bruce has done this season. Playing with an unhappy crowd in the stadium could hurt the morale of the team.
He said via the Chronicle: “Newcastle, on the other hand, are sinking. It pains me to say because I am a fan of Bruce – I have never hidden that – but the toxicity around them, together with crippled confidence and big injuries, is dragging them down.
“We are all looking forward to seeing fans back inside stadiums, but I’d argue that Newcastle are better off playing behind closed doors for as long as possible, as the discontent is so apparent.
“It isn’t helpful. I love them as a club, but I’d now have them as favourites for the last relegation place.”
Newcastle were already without Callum Wilson due to a hamstring problem, and they lost Miguel Almiron to an injury in their most recent game.
Both players have been hugely influential for the Magpies this season, and their absence makes it harder for the club to beat the drop.
Going back down to the Championship could be catastrophic for Newcastle in terms of prestige and finances.
Bruce will hope that Wilson and Almiron can return to action soon and guide the Magpies to safety this season.