Liverpool do not have a clear No 1 and have missed out by not signing Joe Hart, Danny Mills has told Premier League Daily.
Hart, who is on loan with Italian side Torino from City, was available after being deemed surplus to requirements by Pep Guardiola but Liverpool boss Jurgen Klopp had already signed Loris Karius from Mainz 05.
However, the 23-year-old Karius has struggled in his debut season at Anfield and was dropped for the Reds' 3-0 victory at Middlesbrough on Wednesday following his recent blunders against Bournemouth and West Ham, with Simon Mignolet replacing him.
Mills feels Liverpool should have brought in the experienced Hart when they had the opportunity.
"Looking at the goalkeeping errors we have seen in recent weeks, I think a lot of people have missed out on Joe Hart," Mills told Premier League Daily.
Klopp said after the win over Middlesbrough there is "no time-frame" on when Karius could be restored to the Liverpool starting line-up.
Mills can see why Klopp decided to take Karius out of the team following his recent errors but he believes the uncertainty surrounding who is first-choice goalkeeper could have a detrimental effect on Liverpool's season going forward.
"There has been an awful lot of speculation and an awful lot of talk about Karius in the last couple of weeks," Mills said.
"Maybe he decided the pressure was a bit too much. It's tough as a goalkeeper, one mistake costs you a goal, and it's as simple as that.
"We've always known Mignolet is a fantastic shot stopper. I have questioned his presence in the 18-yard box and his ability to deal with crosses under pressure, that's where he's maybe struggled in the past.
"But it's his decision, it's worked out for now, Mignolet didn't have a lot to do, that one shot he had to save, he did very, very well.
"I don't think there's a lot between the keepers, that's maybe the big problem at Liverpool, there's not a clear number one or clear number two that you have at most clubs.
"As a player, you like to know, whether your number one or number two, where you stand. Even as an outfield player, 'am I in this week? Am I in next week?'
"You like to consistency and if you're going to be number two, it's not a problem, you know you have to fight for the number one place and when you get your chance, and you've got to take it.
"As long as Klopp makes that clear to the players, who he prefers at a certain time, it shouldn't be too much of a problem."