I don't know if there is any truth in it but i heard (i think from Mark) that Genoa have the right to buy 50% of Criscito's contract for 5.8m eur.
In that case, since both teams will own half of the contract, it will be up to the teams to decide what to do next. They'll have to decide if they'll leave it that way (both teams to own 50%) or if one of the teams wants to sell the other 50%, they have to decide where will Criscito play next year etc.
In case they can't decide on any of this, then it goes to blind bids where both teams offer money for the other 50% of Criscito. The team that offers more gets Criscito in the end.