With his future at Old Trafford far from certain, the centre-back has been putting the hard work in over the summer.
Maguire is said to be dropped and replaced by Bruno Fernandes as United's captain ahead of the new campaign. The England international started just eight Premier League matches last season, with Raphael Varane and Lisandro Martinez the preferred options for Red Devils manager Erik ten Hag.
The England international is set to commence work on his fifth campaign at Old Trafford having joined in an £80million deal, a record fee for a defender.
Despite the prospect of consistent game time remaining uncertain, Maguire has still put the effort in to be part of Ten Hag's squad.
In a post on Instagram captioned with 'No Limits. No excuses', he has been put through his paces out in Portugal.
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The 30-year-old was also pictured at the training camp with Red Devils teammate Diogo Dalot, as well as Love Island star Brad McLelland, who played for non-league sides Alnwick Town and Amble Tavern before appearing on the show.
Maguire appears to have called on the guidance of former Chelsea star Carvalho, who was no stranger to success in England.
During his six seasons at the Blues, he won three Premier League titles as well as three FA Cups and two League Cups.
His debut campaign saw him play in a Chelsea side that conceded just 15 goals in the top flight, a Premier League record.
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Carvalho's expertise could therefore help put Maguire back on the right track, but potentially at another club.
The Manchester Evening News have reported that United have named a starting price of £50million for the centre-back.
However, talkSPORT's Alex Crook believes he could very well remain on the books at United come the end of the summer.]
"This goes back to balancing the books and FFP [Financial Fair Play]. Obviously they paid £80million, a record for a defender, they're not going to get that back but they need to claw back as much as possible if they are to sell Maguire to help balance the books.
"I don't think Ten Hag is forcibly pushing Maguire out of the exit door but I think what's clear is that Maguire is nowhere near first choice.
"Clearly Varane and Martinez are the two first choice centre-backs and when they're not fit Luke Shaw more often than not has tended to fill in.
"So, if Maguire has ambitions to start for England at the European Championships, I think he has to push for a move this summer. But, he's got a million reasons not to because in his contract, he got a nice pay rise as a result of qualifying for the Champions League.
"Again, if you're asking me now, do I expect Maguire to still be a United player come September 1? I think I probably do."