Manchester United confirmed Rashford would have to undergo an operation to resolve a longstanding issue with his left shoulder, having played through the pain for much of the previous campaign.

The England international – who was part of Gareth Southgate's squad for Euro 2020 – had the procedure last Friday. While his club have not made it clear how long he will be out, reports have suggested it could be a 12-week recovery process.

However, Rashford appeared in good spirits on Tuesday as he provided a fitness update on Twitter.

"Thank you for all the well wishes. I had my surgery on Friday morning and everything went very well," he wrote to accompany a picture of him relaxing in a chair with his feet up.

"A little sore but other than that I'm feeling good. Hope you're all having a great day!"

United opens its Premier League campaign with a home game against Leeds United on Sunday (AEST).

Rashford scored 11 goals in the competition last term, helping Ole Gunnar Solskjaer's squad finish second to Manchester City. He also scored twice as the Red Devils made the Europa League final, albeit they missed out on securing the trophy when losing to Villarreal on penalties.

There was also shoot-out disappointment for the 23-year-old with his country in Euro 2020 too, Rashford one of three England players to miss in the Wembley final defeat to Italy.

Since Solskjaer's first match in charge in December 2018, Victor Lindelof (10,289 minutes) is the only player to feature more regularly for the Red Devils than Rashford (9,671 minutes) across all competitions.

Still, United is not short of attacking options in his absence. Rashford's international colleague Jadon Sancho has arrived in the close-season, with the former Borussia Dortmund forward undergoing his first training session with the United squad on Monday.