The shot-stopper has missed the last two games against Basel and West Ham due to injury, despite playing against Arsenal before that.
He pulled out of the Brighton match during the warm-up, but returned to action against his former club Arsenal just days later, before sitting out again.
But Villa are hopeful he will prove his fitness in time to play United at Villa Park.
Head coach Unai Emery said: “Emi is progressing well. He is training individually and feeling better, much better.
“Tomorrow we will decide if he is available for Sunday.”
Meanwhile, Harvey Elliott has not trained due to sickness, while a few other players will sit out the match.
“Harvey Elliott is sick and didn’t train today or yesterday," Emery added.
“Tyrone Mings is still injured, but is getting better. In a few weeks he will join us.
“Pau Torres is the same, back in one or two weeks, something like that. Ross Barkley is out for longer.
"The other players, if all goes well, will train tomorrow and be available for Sunday.”
Villa are targeting their 10th consecutive win all in all competitions as they take on United.
But the Villa boss wants to see his side remain 'humble' and remain focused on their task against the Red Devils.
He added: “Be humble, and work like we are doing the last years, but especially the last two months, I think the players, after our poor start, they involved with me as well in the demand I have, and we are trying to set in the squad every day, how we want to work, how we want to be demanding ourselves, and how we can get consistency.
“And the players, they responded fantastic, and they were aware, two months ago more or less, about how we needed to react, and we did it.
“But, of course, now, it’s the moment we must be humble and to understand, if we are not keeping the same consistency like we are and being demanding like we are, we can lose against every team in the Premier League.”
United have also won their last two away matches in the Premier League and Emery is aware of the danger they pose.
He said: “Very difficult. Of course, it’s United. And United, not only for (their) history as well, how they are trying to build a team, and they are, this year, of course, trying to get (a) top position.
“They are performing very, very well away (from home), very well. And winning matches and performing and playing fantastic.
“At home, they are having some more problems than away, but I respect them a lot because their history, how they are performing, with the coach, new coach, last year and this year I think they are getting better.
“And with the players they have, they have very, very good players and offensively they are performing fantastic.
“And we are ready, but we are respecting them and we are being humble. Be humble, especially in this moment, we must be humble, to try to understand why we are performing like we are.”