The Spanish midfielder was left at home instead of travelling to Ukraine to take part in the club's 2-1 defeat to Shakhtar Donetsk in the Champions League on Wednesday, on account of not being "fully fit".
United manager Jose Mourinho accused long-time rival Guardiola of mind games earlier this week, insisting he would not "lie" about the fitness of his players.
Mourinho faced a similar predicament in the build-up to United's 3-1 win over Arsenal, with Arsene Wenger claiming that Alexandre Lacazette was unfit, before fielding the Frenchman at the Emirates Stadium.
Asked about both the form of Raheem Sterling - who has scored nine goals and provided four assists in 13 Premier League appearances - and the fitness of Silva, Guardiola replied: "At 23 years old, always you can do better. You have a lot of distance to achieve your best level.
"Sterling has a lot of things to improve and that’s why he will have a long career. Silva is going to play."
City are currently eight points ahead of United in the Premier League, and can take their lead into double figures with a victory at Old Trafford this weekend.
Guardiola's side have yet to lose in domestic competition, only dropping points in a 1-1 draw with Everton in August.
United, meanwhile, are City's closest challengers, having taken 35 points from 15 games. The only blots on their copybook come in the form of defeats to Chelsea and Huddersfield Town, along with draws with Liverpool and Stoke City.