Guardiola had suggested that Silva was doubtful for the game after he had reported feeling "uncomfortable" following his match-winning 83rd-minute goal against West Ham at the Etihad last weekend.
Silva did not travel with the City squad to Ukraine for their final Champions League group match against Shakhtar Donetsk.
"He's going to play. He's going to play - after the game he had a bit of doubt that's why I said it but today he arrived and said he's really good so he's going to play," Guardiola told reporters.
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However, the City manager will have to wait until training on Saturday before deciding on whether centre-half Vincent Kompany and left back Fabian Delph are ready to face Jose Mourinho's side.
"Kompany, before the game against Shakhtar, felt something, was not comfortable and couldn't play. Delph was sick, vomited and had fever the day before. Today they are off so I don't know but tomorrow we will check how the conditions are," Guardiola said.
(Reporting by Simon Evans, editing by Ed Osmond)
