John Stones limped out of England's Nations League game against Germany at Wembley.
Walker, who has just returned from a muscle injury, started England's 1-0 defeat to Italy on Friday.
City host neighbours Manchester United in the Premier League on Sunday, 14:00 BST.
Both Stones and Walker have seen the start to their season disrupted by injury.
Stones missed City's Champions League victory at Sevilla while right-back Walker suffered a problem in the Premier League draw at Aston Villa at the start of September.
Source: m.allfootballapp.com