The Frenchman has finally completed his world-record return to Manchester United.
The Frenchman made his long-awaited return to Old Trafford from Juventus on Tuesday, with the Red Devils stumping up an initial fee of £89m for a player that left the club in 2012 for just £800,000.
His arrival comes after a heavily protracted transfer saga, but United have finally secured the services of the 23-year-old, who won four consecutive Serie A titles with Juventus, in addition to two Coppa Italias and an Italian Super Cup double.
But, despite having matured during his time in Italy, Souness feels Manchester United have paid over the odds for their former player.
"For a midfield player of his standing it's too much money," he told Sky Sports. "No matter what he achieves, I don't think he's worth £89m.
"For that kind of money you're looking for the finished article, someone who changes games on a regular basis - I've not witnessed that from Pogba yet.
"I'm yet to be convinced. He has a great deal of potential, and he's at a great age but £89m is too much for me for what he has shown to me last year and at Euro 2016.
"The really big money goes for the game-changers who get 30, 40 and, in Luis Suarez's case, 50 goals a season. I don't see that. I don't see the value in it."
Pogba made 124 appearances for Juventus over a four-year spell, scoring 28 goals and developing into one of the most sought-after footballers in the world.
The France international is United's fourth major signing of the summer, joining Eric Bailly, Henrikh Mkhitaryan and Zlatan Ibrahimovic in the club's ranks.
Souness does not doubt Pogba's ability however, but is not convinced on whether he can consistently perform.
"You have to say Jose Mourinho has been backed to the hilt by the club in this," he continued. "Manchester United, like all the giant clubs out there, have had to pay a premium.
"However, the boy is a talent and it's not his fault they've paid that much."
Pogba will be in contention to begin repaying his new employers when United face Bournemouth in their Premier League opener on Sunday.