McAteer, who made exactly 100 appearances for Liverpool between 1995-1999, believes Liverpool's first choice goalkeeper Simon Mignolet is becoming complacent because of the lack of competition for his starting place.
The ex-Republic of Ireland international told Starsport that the Belgian, former Sunderland shotstopper has become too 'comfortable', and with only Brad Jones behind him, he knows his position is the team is safe.
McAteer said: "Simon Mignolet maybe is too comfortable and too complacent and it won't do any harm getting someone in.
"With Brad Jones behind him, he probably thinks his place in the team is safe. If he makes a mistake he knows he'll start the next game regardless.
Liverpool have been strongly linked with current free agent keeper Victor Valdes, who allowed his contract to expire at Barcelona earlier this summer.
Brendan Rodgers is reportedly a huge admirer of the 32-year-old, who has won every team trophy in the modern game. However a move won't materialise until the Spaniard recovers from cruciate knee ligament damage sometime in October.
And when asked if he thought Valdes would be viable option the Liverpool legend said: "Valdes is an option and yes, I think he would come in and compete.
"You need to keep players on their toes so they know there is competition for their place."
Mignolet has already conceded eight goals in five games this season, but it would be unfair to pin all the blame on him. Liverpool's defence has been quite shaky so far this season, and some of them do not appear to have learnt from the mistakes that cost them the Premier League title to Manchester City last season.