Vidic selected in squad for Sunderland clash
The Serbian international has played only five matches this season and had knee surgery in September.
The United defence has been unconvincing in Vidic's absence, conceding 23 goals in 16 Premier League matches, and Ferguson told a news conference on Friday that his return was a huge boost.
"It's a big, big win to have him back in the squad - his ability to head the ball, his captaincy. We hope we've given him the proper rehab," Ferguson said.
"We'll give him a chance and we hope he sails through it. I don't know whether he will start tomorrow - he's only played about 10 games in the last 12 months, which is not like Nemanja."
Vidic's return is all the more important because Jonny Evans is unavailable with a hamstring injury he suffered in last weekend's Manchester derby win.
Ferguson said Nani was still unavailable and Shinji Kagawa was back in training.
Sunday's last gasp 3-2 win over Manchesters City handed United a six-point lead at the top of the table, and Ferguson said that took some pressure off his side.
"I'm happy with six points. It's City's challenge to try and catch," he said.
Saturday's opponents last met on the final day of last season at the Stadium of Light, where United thought they had won the Premier League title with their 1-0 victory, until news filtered through of Manchester City's remarkable last-gasp winner.
City's win prompted celebrations from the Sunderland fans, which upset many United players.
"Their fans' reaction on the last day was disappointing," Ferguson said.
"When you think about the players we've given them over the years, including Evans and [Danny] Simpson, who helped them win promotion. I don't think it was malicious from their fans, just foolishness, they were just enjoying the moment."
Sunderland face the daunting trip to Old Trafford missing up to five frontline players, with Adam Johnson, Danny Rose and Phil Bardsley all facing late fitness tests.
Captain Lee Cattermole and former United man Wes Brown are not expected to return to action until next year.
Sunderland were boosted by their 3-0 win over Reading on Tuesday but remain perilously close to the relegation zone with 16 points from as many matches.