The Brazilian club were close to signing the Manchester City striker over the summer before a reported £40m deal broke down.
Now they say that the Argentinian is worth less after the recent furore surrounding his alleged refusal to come off the substitutes' bench during City's Champions League game against Bayern Munich last month.
"We made an offer in the window, he is a player who interests us, but only in January will we see if we have a chance," Sanches told the Daily Mail.
"He is not worth £40m - we will make an offer well below it. I don't know if they will accept it, the [financial] gap is huge. I have a value in mind but I won't say what it is.
"The written offer of £40m isn't worth anything now. After all of the problems, he should be worth less. What if he brings these problems here?"
City confirmed on Wednesday evening that Tevez will face disciplinary action following the events in Germany.