The Frenchman tweaked his knee in last Sunday's Community Shield when United came from behind to beat neighbours Manchester City 3-2 at Wembley.
"We'll give him until tomorrow but he is doubtful," Ferguson told a news conference ahead of Sunday's trip to West Brom.
One player who will definitely miss out is Mexican striker Javier Hernandez who suffered a concussion during their pre-season tour of the United States.
"Chicharito is still, I would say, 10 days away from taking part in any football," said Ferguson. "It's not a concern, just a precaution given the fact had a concussion a couple of years back."
United begin the defence of their title away from home, where they struggled last term and gathered only 25 points from a possible 57.
"We had the worst record away from home in the Premier division and the best home record in the Premier division so what do we do about it? I don't know. It was surprising the number of points we dropped away from home I must say," Ferguson said.
"I agree with you [that we can't bank on our home form this season]."
They go into the opener in good spirits after fighting back from two goals down against City thanks to an inspired second-half performance from youngsters such as midfielder Tom Cleverley and defender Phil Jones.
Whether his young players have done enough to earn first-team spots remains to be seen but they are certainly on Ferguson's radar.
"We've got a strong squad... I think picking a team is maybe easier with the second-half performance last week in some ways but we still have to respect the experience of the ones who came off at halftime," the manager said.
Having marched to a record 19th league title last season, United have been installed as favourites to win another.
"Probably the fact we won so well last Sunday [has made us favourites]," said Ferguson before pointing out that Manchester City, Chelsea, Liverpool and Arsenal were all contenders.
"We used to talk about top four but now we talk about top six really."
