Rashford, 28, has not played for Manchester United since December 12, 2024, having spent last season on loan at Barcelona. The Spanish club opted not to trigger their £26m purchase option, leaving him in limbo and set to return to Old Trafford as the club's highest earner on £375,000 a week from next week.
United's private preference is for Rashford to be sold. The forward himself publicly expressed a desire to remain at Barcelona on a permanent basis before their decision not to buy him was confirmed.
Maguire, who has known Rashford since their first England appearance together in 2017 and became his club colleague in 2019, was measured in his public support for a player he described warmly.
"I have an amazing relationship with Marcus and have had great times with him over the years," Maguire told The Rest is Football podcast. "I know what a wonderful player he can be.
"It's up to the club and Marcus to find a mutual agreement. Of course, if Marcus does come back, we want him to play and be happy and confident.
"It needs to be right for himself, it needs to be right for the club. But everyone knows what a great player Marcus can be for whatever club he plays for next season."
The 33-year-old is a member of the six-man leadership group at United. Crysencio Summerville of West Ham United has been linked as a potential left-sided replacement as the club look to resolve the Rashford situation and strengthen wide.