Realistically, how much can we get for him if he things don't pan out come the end of the season?
Selling Can, Ramsey and Rabiot for a combined 80-90 million (not to mention their insane wages) gives us some serious plusvalenza (we could sign two quality mids).
Of course, we would then have to keep Matuidi, Pjanic, Bentancur, and possibly Berna (as a midfield option). Khedira can leave on a free.