De Gea: His role is already in question due to his stylistic limitations, and also his contract is up. With a bit of decline he'll be vulnerable.
Shaw: If he can't return to something like 20/21 form, it's hard to see how he'll be a credible No1 option at LB going forward. Also challenged by Malacia.
Maguire: Has to return to at least close to his previous top level (20/21) to salvage his role as a major player in the squad. Another season like last year's, and he's done.
Lindelof: One of the few who could probably more or less retain his place in the pecking order with a season roughly similar to the last
Dalot: He's still a long way away from being a viable starting RB on a top team, and if he doesn't make major strides in that direction this year, he may find the team runs out of patience
Fred and McTominay: Both will I think have reduced roles, which means less pressure.
Bruno: Has largely carried the team since he arrived, and faces huge pressure to bring that impact into a new system and a new role
vd Beek: Has a lot to prove and the clock is ticking on him as a PL player, but on the other hand the only way things can go for him is up.
Rashford: Major pressure. If he can't deliver a strong improvement on last season, his future at United may look short
Elanga: He's under pressure to improve if he wants to cement his place in the squad, but I doubt he's written off even if he should regress.
Sancho: Must manage to deliver quality with greater consistency this year if he's to avoid a reputation as an expensive bust.
Ronaldo: Given his age, I think it would be viewed with some understanding if his production should tail off a bit. Not by himself though. He's the saviour. There's never going to be anything other than huge pressure on him.
Martial: He's basically viewed as a lost cause who we'd move if we could, so in that sense there's not much pressure. Should he want to reclaim his place in the squad, he's facing a huge challenge though. So I guess it depends on what he wants.