United hold a three-point lead over Manchester City with eight games remaining in the season, but could find themselves in second by the time they meet Rovers as Roberto Mancini's men face Sunderland at home on Saturday.
Ferguson had injury concerns over Ferdinand, as he limped out of the win over Fulham, while Nani has been struggling with an ankle injury.
The game will come too soon for the Portuguese winger, who has not played since March 8, but Ferdinand has shrugged off a back complaint and will feature in the travelling party to Blackburn.
"We have the same squad as on Monday night, there are no changes," Ferguson said. "Rio is okay - he just felt a bit stiff. We know the situation with that - we addressed it right away and put [Chris] Smalling on. He's fine.
"We expect Nani to train tomorrow [Friday] but the game will come too soon for him. [Anders] Lindegaard was training very well and maybe overdid it. We've given him a week off and he should be back before the end of the season."
Blackburn claimed a shock win at United on New Year's Eve and Ferguson is expecting a tough test on Monday.
"Blackburn is always a difficult type of game," he said. "It's always a bit feisty and has a local derby feeling about it. Last season we came back from a goal down to win the league. We expect a difficult game - that's the way all the games will be.
"You can look at all the games and say Blackburn, QPR, Wigan and Villa are all fighting for their lives. Hopefully we can navigate them. It's important for us to make sure we get in front in games."