Sergio Aguero says he is still not at full fitness ahead of Manchester City's massive clash with Chelsea this weekend.

The Argentine striker played the final 27 minutes of City's 3-0 victory over West Bromwich Albion on Monday night after having an interrupted summer with Copa America duties in Chile.

As the Sky Blues prepare to host reigning champions Chelsea at the Etihad on Sunday, Aguero admits he may not be in bright enough condition to be part of Manuel Pellegrini's initial XI for the visit of Jose Mourinho's men.

"Whether I start or not remains to be seen," he told the club's official website.

"I'm trying to get there and be in top condition but, arriving for pre-season later having taken part in the Copa America with Argentina, means I need some additional time.

"With the whole season in mind, what matters the most is that I get in top form and don't take any risks."