The Frenchman has been heavily linked with a move away from the Etihad Stadium this summer after arriving to pre-season out of shape, but Guardiola suggests he has undoubted quality and can be a great asset to the team if he continues to work hard.
"Nasri can stay," said Guardiola when asked of the 29-year-old after Sunday's 3-1 win over West Ham United.
"Samir arrived overweight but after seven days, ten days, it was fantastic how he trained.
"His quality is another level. It depends on him. If he wants to help us and stay to be part of something, it depends on him."