Aguero missed City’s 3-0 win over Watford in the FA Cup third round after suffering the problem late in the 3-0 win over Stoke on New Year’s Day.
‘The studies confirmed I have a torn muscle,’ Aguero wrote on his Twitter account tonight. ‘We have to keep on thinking positive and try to recover in the best way possible.
‘For that, I’ve travelled to Italy where a specialist is treating me. I’ll keep you up to date in how the injury evolves.’
Manager Roberto Mancini initially said he hoped to have to his joint top-scorer back for next weekend’s trip to Arsenal, but that now looks impossible for a match that is becoming more and more difficult by the day.
Mancini will already head to the Emirates without the suspended Samir Nasri, and with Yaya Touré away on African Cup of Nations duty, the champions go into the match missing three of their key players.