The 28-year-old England attacker is in advanced talks with Barcelona who have a £26M optional buy clause in their loan for the forward whose future at United looks to be over.
Reports state that multiple club-to-club meetings have already taken place this year, starting in January as the Spanish decide on whether to trigger his loan clause.
Speaking to talkSPORT Bet Casino, McCoist believes a move away would suit the England international who has thrived in Spain so far.
“I definitely think so. I think both parties are the same with Scott McTominay.
“I think it would be interesting. If you ask Marcus, clearly he's got love for United, of course that goes without saying. But I think he's at a stage now, he's got a taste of it again at Barcelona.
“If they could come to some agreement, I think he'd be far, far better staying in Barcelona and getting all his football again rather than come back to United, would that be a big question mark.
“The eyes should be on him again. I think he's enjoying life, I would never use the word anonymity because it's not anonymity, but there's certainly less profile and pressure on him from this country.
“I get it, it will probably be large in Spain and Barcelona, of course it will be, but the pressure that was on him here at United from press and fans and all that. I don't think he'll be missing that for a minute.”
Rashford has impressed this season with 10 goals and 13 assists so far under manager Hansi Flick who admires the forward who is now in his prime. A move away looks likely ahead of what will be a busy summer for Rashford who also has the World Cup with England.