The Portuguese midfielder was withdrawn in the first half of Tuesday's 3-1 win over Red Star Belgrade in the UEFA Champions League and is likely to miss Saturday's fixture against Nottingham Forest.
"We are in trouble but I am not going to say, 'Oh, we have a lot of injuries.'"
"We have five important players injured,” said Guardiola. “Sustaining that for a long time will be difficult but it is what it is. We cannot have 35 players because that will be chaos for the clubs and go bankrupt.
"Unfortunately it’s a long time for Kevin. John didn’t play. Maybe 'Kova' is coming back. Jack has a week or 10 days.
"It is what it is. I prefer to use everyone and, with the players that we have, go for it."
Pep heaps praise on Rodri
Guardiola can at least continue to call upon Rodri, who delivered a Man of the Match performance last night and scored City's third goal. His manager feels there isn't a better player in the world in his position.
"Right now, yeah, he is the best," Guardiola said. "Hopefully he can be better and improve but he is an extraordinary holding midfielder.
"We were lucky the club signed this player, and when he arrived he was not this type of player. Of course he plays an amount of games and now he is one of the captains. He is a top-class player.
"The goal is top-class but defensively, offensively he reads the play and spaces and knows exactly where men are free.
"Close to the box he is so dangerous. He loves to arrive in the final third and dribble and shoot. He is playing really, really well."