Erik ten Hag's arrival at Old Trafford should see the playing squad change massively with a number of incomings and outgoings expected.
United have seen six first-team players leave after the end of their contracts, including Paul Pogba and Jesse Lingard.
However, many more in the current squad could find themselves pushed out of the exit door as well to make way for new players.
Tyrell Malacia has been confirmed as their first signing, but there should be a lot more.
Well, talkSPORT.com decided to take a look at the biggest Manchester United transfer rumours…
Cristiano Ronaldo
Wantaway superstar Ronaldo is not for sale, talkSPORT understands.
The Portugal sensation, 37, has asked to leave Old Trafford and is not taking part in their pre-season tour.
Reports have emerged to suggest the Red Devils are prepared to sell Ronaldo this summer - but talkSPORT transfer guru Alex Crook insists that is not true.
He said: "He has been granted additional time off to deal with a family issue, and because of the nature of the issue, they can't speculate when he will join the side.
"But they reiterated to me that he remains under contract with Man United, he isn't for sale.
"These stories that have been coming out saying that they are now accepting that he will leave and they have a price tag in their head - I've been told that isn't the case."
Antony
Red Devils manager Ten Hag is on course to sign one of his former Ajax players Antony, talkSPORT understands.
talkSPORT's Crook said: "I think United are definitely in for Antony.
"His numbers for much of the season were decent, I think he missed the end of the campaign injured but he's obviously someone that Erik ten Hag knows well.
"There's been talk of a £40million bid going in for him, certainly my sources haven't distanced themselves from those rumours so I think Antony is a target.
"In fact I've had a text from somebody else saying 'if he doesn't become a Manchester United player this summer, I would be surprised'."
Christian Eriksen
The Red Devils look set to make the former Tottenham man one of their next summer signings after the player agreed a three-year deal.
The 30-year-old held talks with several top-flight clubs, but it came down to Brentford and Manchester United.
And after talks with Erik ten Hag, Eriksen has committed his future to Old Trafford.
Eriksen impressed for the Bees in the second half of last season, and it appears as if it was a tough decision, but the Red Devils have won the battle, and the Dane will be part of Ten Hag's squad this season.
Lisandro Martinez
Manchester United have agreed a £46million fee with Ajax for defender Lisandro Martinez, talkSPORT understands.
The Argentine centre-back was kept out of Ajax training on Thursday morning ahead of a move to Old Trafford.
It will see the 24-year-old reunite with manager Erik ten Hag following his appointment at the Red Devils.
Martinez was also being tracked by Premier League rivals Arsenal, but it is United who have won the race.
"Manchester United have now agreed a £46m fee with Ajax for Lisandro Martinez," talkSPORT's Alex Crook told White and Jordan.
"He's been kept away from Ajax training this morning, according to sources in the Netherlands, to tie up this move to Old Trafford.
"He will join United this weekend on their pre-season tour of Australia.
"This is a big deal for Erik ten Hag. He was presented with Villarreal defender Pau Torres as a possible centre-back option, but the coach said no.
"He wanted Martinez from the beginning. Arsenal had two bids rejected by Ajax, and the Gunners took a back seat when Martinez made it pretty clear he only wanted to go to United to link up with Ten Hag.
"I think symbolically this is a very big transfer for Manchester United."
Frenkie de Jong
This has been one of the longest sagas of the transfer window, but it looks close to coming to a successful conclusion for Manchester United.
The Red Devils and Barcelona finally agreed a fee of £63m plus add-ons for the Dutchman.
However, the midfielder is owed £17m in deferred salary payments, which is still holding up the deal because he, understandably, wants his money.
Chelsea had emerged as contenders for De Jong after Todd Boehly met Barca in Spain last week.
But it appears, once the wage situation is sorted, Ten Hag will get his man.