Aguero could be back for City within a month
Sergio Aguero (below) could be back in action within four weeks.
Manchester City's Argentine hitman told media after he was stretchered off in his country's World Cup qualifier with Equador last week that he expected to be out for a month.
That would rule him out of the derby at Old Trafford on October 25.
But he could be back in action quicker than the two months many predicted he would be out for - and has targeted a return to international football in Argentina's clash with Brazil on November 13.
He says he will take a measured approach to recuperating from the latest in a line of hamstring injuries in a bid to avoid suffering the same fate again.
He is quoted as saying: "Hopefully I can play against Brazil, but I must heal the injury slowly so that it does suffer more.
"This is an injury that you have to recover slowly from, but of course I want to recover quickly." To make the Brazil game, City and Argentina would hope that Aguero would have played at least a part of a club game to prove his fitness.
Manager Manuel Pellegrini will not want a repeat of the scenario that has seen Vincent Kompany join up with his national team against club wishes having not fully recovered from injury.
Aguero (27) is set to miss the derby as well as City's two crucial Champions League fixtures against Sevilla on October 21 and November 3.
Aguero underwent tests in Argentina on Friday before returning to Manchester.
City play Bournemouth, Sevilla twice, United, Crystal Palace, Norwich and Aston Villa before the date of the Argentina Brazil game.
The Argentine Football Association said last week: "The studies we did today show that Sergio Aguero has a grade-two muscle tear."