Bournemouth have reportedly accepted a bid of £41m from City for their Dutch centre-back Ake.
But Carragher took to Twitter to express his concerns with the prospect of City playing with two left-footed centre-backs.
"I like Nathan Ake & I think he will suit Man City, but with Laporte a guaranteed starter I'm not convinced two left footed centre backs works?" he said.
"I know right footed players play together but it never feels right the other way round to me! Left back or a Back 3."
When one Twitter user challenged his views, claiming the only reason City were leaky at the back last season was due to Laporte's long-term injury, Carragher added: "Is Laporte injury prone or he just had a bad injury? There is a difference. If Laporte is fit he plays! I just think it's interesting to see how Pep gets Ake into the team when Laporte is fit!"