The Scot believes the former Barcelona man will start despite being required to meet up with the Ivory Coast squad ahead of the African Cup of Nations after Roberto Mancini's request to select the midfielder for the third-round tie was denied by his national boss Francois Zahoui.
"I'm not sure that [Yaya] Toure won't be available," Sir Alex told reporters. "He probably will.
"I don't know the whole background, but apparently he doesn't need to meet up until Monday, which suggests he should be playing on Sunday.
"It only affects one player [Yaya] really, because Kolo hasn't played that much."
Sir Alex also believes the loss of the midfielder and his brother Kolo will not be detrimental to City’s Premier League title challenge.
The 70-year-old feels clubs in a similar position in the past have coped well without their African Cup of Nations players.
"All the teams who have had African players over the years have never really suffered much.
"If you look back at the records, they all seem to have sailed through it - Arsenal and Chelsea have always been there.
"So I don't think it has a huge impact, to be honest. When you've got a big squad, there's plenty to cope without those players until they come back."
The Red Devils' manager is confident of getting a result at the Etihad Stadium despite United’s poor league form and is backing his experienced players to come through for his team.
He added: “City have a strong squad and an experienced squad. So it’s not unexpected where they are at the moment. But they also know we’re right behind them.
“It doesn’t matter what situation we’re in, we’d expect to get a result against City. If questions are being asked about us at the moment, it’s only because we’ve had two bad results.
“Only a couple of weeks ago people were saying how important our experience was going to be and I think it will be important.”
Sir Alex also revealed his frustration at his players following their 3-0 defeat to Newcastle on Wednesday, as he believed his side were strong enough to get a positive result out of the match.
“The disappointing thing for me the other night was we had a really experienced team out,” he said.
“Some of them were short of a game or two but, nonetheless, we carried a lot of experience into that game.”
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