Shearer is concerned the Toon’s failure to fill the void left by the France international’s £20million switch to Paris St Germain will leave the rest of the squad questioning the clubs ambition, and possibly their own futures.
Joe Kinnear paid the price for his failed moves for Lyon’s Clement Grenier and Montpellier star Remy Cabella over January, as he resigned as director of football earlier in the week.
Shearer believes Newcastle have made a big mistake in not having a replacement for Cabaye in place, and the move has sent out the wrong message to supporters, as well as Alan Pardew’s squad.
“Joe Kinnear was quoted as saying that no-one would be leaving in January,” Shearer said.
“But if you’re going to let your best player go, you have to have a plan for someone to come in. You can’t let Cabaye leave and then bring no-one else in. That just can’t happen.
“It sends a bad message out to the fans and, if you’re a player in that dressing room, you must be thinking, ‘where are we going?’”
Newcastle’s season is in danger of fizzling out, with the club having suffered five defeats in their last seven.
Shearer also revealed his disappointment at the clubs failure to have a run in either of the major cup competitions.
“I don’t get them resting players in those competitions because these are the trophies that the likes of Newcastle need to go for. Resting players in cup competitions I just don’t get,” he said.
“It’s not as if they are in Europe and playing 65 games this season. They went out at the first hurdle in the FA Cup, and played three games in the Capital One Cup.”