The Argentine is set to undergo a scan on Monday to reveal the extent of the problem following a collision with Nathaniel Clyne in Sunday's win over Southampton.
Manchester City striker Sergio Aguero has eased concerns over his knee injury by confirming there is no significant damage to the joint.
The Argentina international was stretchered off after just 13 minutes of City's Premier League opener against Southampton following a collision with fullback Nathaniel Clyne.
The 24-year-old is now set to undergo a scan on Monday to reveal the extent of the problem but the forward remains upbeat about his situation.
"The studies I had done revealed there's no significant injury but it was a very tough hit to my knee," Aguero posted on Twitter. "Tomorrow, the physicians will evaluate the time it will take for me to recover. I can't muster words to thank for your concern and with this much support, I'll probably get back up on my feet soon."
Manchester City won the match 3-2 but found themselves trailing after 68 minutes as goals from Rickie Lambert and Steven Davis cancelled out Carlos Tevez's opener. Edin Dzeko drew his side level in the 72nd minute before Samir Nasri grabbed a late winner.
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