Aguero has made just five Premier League appearances this season and has missed City's past three games in all competitions while in self-isolation despite testing negative for COVID-19.
Guardiola has used Gabriel Jesus, Kevin De Bruyne and Ferran Torres in the central attacking role during the Argentina international's absence but is not interested in bringing in further options.
The City boss simply replied "no" when asked if the club could look to bolster their options in January after he confirmed Aguero would not return to face Villa.
"He is not ready. He is still isolating," Guardiola said at a news conference on Tuesday.
"We need Aguero, we miss him. The numbers speak for themselves. He's the best striker in our history.