Mane moved to German champions Bayern Munich this summer and his spot on the left wing is now occupied by Colombia international Luis Diaz.
Liverpool currently have two wins and three draws from six games in the Premier League and look a far cry from the side that notched four wins and two draws by this stage of the 2021/22 season.
Nevin highlighted the fact that Mane would always take another player with him every time he drove infield, leaving acres of space for Robertson to exploit out on the left flank.
Diaz is a different kind of player, according to Nevin, and that has provided manager Jurgen Klopp with a tactical puzzle to solve, though he is confident the German will do so.
“There’s a couple of technical things that have changed with Liverpool that are not that easy to see”, Nevin said on Off The Ball.
“Andy Robertson used to get the ball a lot down the left-hand side. Always free on the left-hand side, slewing all these balls in all day long and creating lots of goals, not as many of late.
“Is that because Robertson’s a lesser player or is that because Sadio Mane’s gone?
“He used to take that position and drive on, leaving an enormous gap because people were scared of him and ran with him.
“They’ve got a different type of player on the left-hand side most days and it’s stifling that wee bit of their game.
“They’ve got a great bunch of attack-minded players on the left-hand side but it’s also cut off the space for Robertson.
“I suspect Jurgen knows that and is working on it.
“I’m not worried about Liverpool long-term.”
Liverpool travel to Naples for their opening fixture in the group stage of the Champions League on Wednesday, a venue where they lost on both of their last two visits.