Manchester United got through to the FA Cup quarter-finals with a 2-1 win over Reading on Monday night, but United defender Phil Jones suffered an ankle injury.
Nani, who replaced England international Jones in the first half after he picked up an ankle injury, scored the opening goal and set up Javier Hernandez’s strike, before Jobi McAnuff pulled one back for Reading with nine minutes remaining.
United will now play Middlesbrough or Chelsea in the last eight of the FA Cup, but could be without Jones for their next match against Queens Park Rangers.
"We'll have to assess him,” said United manager Sir Alex Ferguson. “It's an ankle injury so I'd imagine he'll not be ready for Saturday anyway – but we'll see what he's like after that."