Lawro believes even United's defensive reserves need to be replaced.
"You're talking about replacing the whole of the back four, at least," said the BBC 5Live pundit.
"They need a right-back because Rafael's not good enough defensively, absolutely no way. (Alex) Buttner would come in for Evra (at left-back) because he'll go, but he (Buttner) isn't good enough.
"(Chris) Smalling has not played enough games and can be quite naïve at times. He's a great athlete but I think his positional play isn't brilliant."
Lawrenson went on: "(Phil) Jones is just a stop-gap in midfield because his feet aren't good enough at all.
"He is someone who has to play at the back and attack the ball - but he needs help.
"Jonny Evans has played lots of games but I think he plays for himself, and some players are like that. There's nothing wrong with that - he has to play 100 per cent for himself just to get through the game.
"So that's another problem - organisation. When the ball comes into their last third they don't look as if they've got great confidence.
"It's a problem - they play like they could concede a goal at any moment."
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