Manchester City striker Sergio Aguero is at the top of Chelsea manager Jose Mourinho’s transfer wishlist in what could be the biggest deal of the summer, [football] direct news understands. The 25-year-old, who has been ruled out for around a fortnight by his club after sustaining his third muscle injury in as many months in the midweek loss to Barcelona, is one of the hottest properties in European football.googletag.cmd.push(function() { googletag.display(“div-gpt-ad-1389116196215-0”); });While several of his team-mates penned long-term contract extensions last summer in the wake of manager Manuel Pellegrini’s arrival, Aguero chose to add only one extra year to his deal at the Etihad Stadium, which runs until June 2017. There is no suggestion that he is unhappy in the North-West or looking for a move at the end of the season, but a source close to Chelsea told FDN that the Argentina international is the man identified by boss Jose Mourinho to end the striker crisis at Stamford Bridge. The west London outfit are aware that even if a deal does become possible, they will have to pay more than they did for 50million club record signing Fernando Torres in 2011. The title favourites have made it to the top of the Premier League table despite lacking a prolific forward, and cannot renew their interest in Manchester United hitman Wayne Rooney as he has committed his future to the champions.