Last weekend, Aguero sustained a knee injury from a challenge by Manchester United's Ashley Young, and despite having recovered sufficiently to feature on the bench against Liverpool in the Champions League, the Argentine was not fully fit.
City will look to end a run of three straight defeats on Saturday evening, but Guardiola has said that the club's top goalscorer must rest his ongoing knee issue.
At a press conference, the 47-year-old told reporters: "After action from Ashley Young, he could not train. After Tuesday's game, he couldn't run.
"Hopefully he will be ready for the last games and World Cup."
Aguero has scored 30 goals from 39 matches in all competitions this season.