The Champions injury list continues to grow, with Aguero the latest who will miss game time.
The Argentine striker came off during the 2-1 win over Chelsea with a possible groin injury.
Guardiola was pessimistic about his condition, but he believes Jesus can fill the void.
"Gabriel has made one of the best starts of this season," the City boss told reporters.
"If Sergio cannot play in the next games, we will see tomorrow and I'm sorry I don't know exactly what he has, Gabriel is our option.
"Of course Sterling can play there in that position but Gabriel is going to play there, sure."