"There must be some kind of a dislike between Shearer and Craig. I think what he has said was totally out of order and completely uncalled for and could be very damaging to a player's career," said the former Blue.
"He obviously doesn't like Craig and felt it was necessary to come out and say what he did, but it was totally disrespectful.
"Don't get me wrong, everyone is entitled to their opinion, but he's not the manager of the club and it's not up to him at all who Newcastle sign.
"Everyone has their problems on and off the field, I certainly had my fair share of mine, but Newcastle have just signed Joey Barton and he is a player who is going through some major problems.
"Barton might even have to go to court for attacking another player in training, and yet Shearer hasn't mentioned anything about this. Why not? Well it just seems like he doesn't like Craig, and that's not on."