City turned down a £40million bid from the Brazilian club last week, with City believed to be holding out for £50million for a player who finished as joint top scorer in the Barclays Premier League last season with 20 goals.
However, speaking on the club's pre-season tour of North America, Mancini said: "We have an agreement with Corinthians but Carlos now is still a City player."
The Sao Paulo club moved for the Argentina striker after being alerted by Tevez's admission earlier this month that he wished to leave City for the sake of his family, with his two children based in his homeland.
Asked whether Tevez would now be discussing personal terms, Mancini replied: "I don't know this. I repeat, at the moment, Carlos is still a City player.'
He added: "I want to wait. At the moment we are here, we are working with the other guys. We should think about this."