Relayed by De Telegraaf, he said: "We have a lot of respect for City, but we are not afraid of them".
"They make the pitch big, that is a quality of them and it is hard for the other teams".
Toure was missing from the matchday squad for the 5-0 mauling of Liverpool at the Etihad Stadium.
Guardiola coached Toure at Barcelona, where the former Ivory Coast worldwide lost his place in the first XI and was transferred to City in 2010.
"Champions League is so demanding, The teams are so physical".
"No, no - it is just a sporting decision", he added.
The 26-year-old Danish worldwide - last year's Eredivisie top scorer with 21 goals in 32 games - will not play in the City match which opens their Group F campaign, Feyenoord announced on Monday.
City rout Reds, United held by Stoke
Mane's challenge when attempting to beat Ederson to a ball over the top was deemed unsafe by referee Jonathan Moss, who issued a red card.
Asked whether Toure would play soon, Guardiola said: "Hopefully - it depends on the player".
Guardiola, meanwhile, confirmed that Ederson has travelled to Holland and could line-up against Feyenoord despite having stitches in his face following his clash with Liverpool's Sadio Mane last weekend.
The 9/5 available on Betfair Sportsbook for City to win alongside Both Teams To Score should appeal but it may pay to play a safer bat and back aManchester City triumph with Over 2.5 Goals at 10/11, knowing Feyenoord are without their most potent striker.
Be that as it may, Kompany is probably not going to go to the Netherlands subsequent to misery the damage to his calf on universal obligation with Belgium. We will see what happens.
City defender John Stones praised the keeper's bravery, saying: "Ederson has got on with it straight away".
"He just wants to be around the team and be in that environment".
The Brazilian goalkeeper has been training in a scrum cap and Guardiola will leave it until tomorrow to decide if to start with him or not.