Souness insists only skipper Harry Maguire is worthy of the shirt.
Writing for The Times, Souness, after slating Aaron Wan-Bissaka, claimed: "The mistakes we have seen from (David) De Gea in the past couple of years suggest he's not playing to the same high standards that earned him the United Player of the Year award in four out of five seasons between 2014 and 2018.
"His form will concern (manager Ole Gunnar) Solskjaer because unless you have a top goalkeeper you'll not be winning any big trophies, so I'm sure that's something he's keeping an eye on.
"(Luke) Shaw has qualities at left back, but could still get himself leaner and meaner, while we'll have to wait and see if Victor Lindelof will be Maguire's long-term partner at centre back.
"Maguire was always going to make a big difference. He's not Virgil van Dijk, but he's a good player.
"Is that going to be United's back five for the next five years? I'm not sure.
"I reckon Solskjaer is still going to be looking at it and questioning some people, asking himself: 'Are they going to win me the Premier League or the Champions League?'
"I'm not sure if that's the five that he'll want for the next five years. The only cert among them on that score is Maguire."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!