Manchester United winger Nani will be out of action for ten days after being substituted during the Champions League win at Braga with a tight hamstring.
But United manager Sir Alex Ferguson said he was hopeful that defender Jonny Evans, who suffered a minor groin strain in the same match, would be fit to play at Aston Villa on Saturday.
Speaking at his Friday morning press conference, Ferguson told reporters: "We're hoping Evans will be okay for Saturday. He's a doubt, although not a serious one.
"Nani is out with a tight hamstring and that will be around 10 days but he should be okay. It's not torn, just tight."
Chris Smalling, who returned to the United picture at Braga after having been out since May with a broken bone in his foot, will step in if Evans is unfit to play.
"We're monitoring the situation with Jonny, and if he doesn't make it then Chris will have to play," Ferguson explained.
"But the great thing is that he's back and there are no issues with him at all. He did very well on Wednesday. We were pleased with that."
League leaders United, who went top of the table after victory against Arsenal at Old Trafford last weekend, have lost only two of their 20 Premier League away games against Villa, who picked up their second win of the season at Sunderland.
And Ferguson warned that Villa's fans would need to be patient as manager Paul Lambert attempts to turn the club's fortunes around.
He said: "It is a daunting task to bring Aston Villa back to where everyone expects them to be. They have a great history. They won the European Cup in 1981. It is correct to say they have not matched their expectations over the years.
"You wonder whether changing managers has a bigger impact than the actual playing standards of the team. They have had quite a few managers, and it takes time to change a team's fortunes.''
Information from the Press Association was used in this report