Keane will test out his hamstring after missing the mid-week Champions League win at Panathinaikos with a strain.
"I'm sure Roy will be desperate to play on Sunday," the United manager told a news conference on Friday. "Hopefully, he will train today and if he trains today he should be okay.
"It wasn't a serious hamstring injury."
Chelsea are unbeaten at home in the league this season, lying second on 32 points, one behind Arsenal.
United, who have an impressive recent record at Stamford Bridge, winning there 3-0 two years ago and drawing 2-2 last season, have 31.
Ferguson argued that, with the top teams so evenly matched, Sunday's game took on added significance.
"I think the three of us are looking very strong.
"None of us is making huge mistakes, which means that when we play each other, they become vital," he said.
"That's what may decide the league this year."
Defenders Gary and Phil Neville and striker Ruud Van Nistelrooy are all set to play for United after being rested on Wednesday night.
Ferguson also had words of praise for Chelsea manager Claudio Ranieri and the way he had rotated his big-name players.
"He uses his full pool and he's done that very well and the bonus for him is that they got a good start to the season and that gives everyone confidence...they believe they are going in the right direction.
"It also gives Claudio Ranieri the confidence to make changes from a position of strength and I think that's an important issue.
"Bringing new players in and getting the start they did is not easy."
"We've had some terrific successes over the years and I think Sunday will be an absolutely brilliant game. With so many good players on the pitch it can't help but be a good game."
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