The news will be a welcome relief to Sir Alex Ferguson who has said Nani is central to his plans to replace Cristiano Ronaldo and Carlos Tevez this season.
Living up to what was expected of him, Nani scored United's opening goal at Wembley and made a significant contribution to his side's first half dominance and it was no coincidence that his departure early on in the second half following a clash with John Terry was the prelude for Chelsea's best period of the game.
Having left the pitch with his arm in a makeshift sling it was feared the 22-year-old would be out of action for at least two weeks, but a scan has given Nani hope he will play for his country on Wednesday against Liechtenstein and for united this Sunday in their opening match of the season against Birmingham.
"I think I can recover in time. We'll see how it turns out," Nani said as he arrived to join the Portuguese squad. "It's painful and it needs treatment [but] it's not a very serious injury. I need to take care of it and I expect to get better in the coming days."
Portugal coach Carlos Queiroz said he was optimistic about having Nani available for the friendly game in Vaduz.
"He can't have any physical contact (on his shoulder) today or tomorrow," Queiroz said but added: "All our expectations are positive."
Nani's possible absence is not the only concern for Ferguson as he looks to clinch a record fourth successive Premier League title.
With goalkeeper Edwin van der Sar out for eight weeks after finger surgery, Ferguson could have done with a solid display from Ben Foster.
Instead the England international produced an error-strewn performance, which included letting Frank Lampard's shot through his gloves for Chelsea's second goal and punching poorly for Ricardo Carvalho's opener.
Ferguson admitted he must decide whether to stick with the youngster or select Tomasz Kuzsczak against Birmingham.
"Knowing Ben and the ability which he has, he should have done better with the second goal," said Ferguson. "However, it was his first big challenge.
"He has waited a long time, has had his injuries, and in pre-season I spread the load between the three 'keepers, and maybe we did not have enough minutes for him."