Vincenzo Guerini is the "club manager" of Fiorentina, which apparently means that he's the mediator and communicator between the technical side and the company side of the club. I'm guessing it's somewhat analogous to at least part of the Director of Football role? Regardless, he's obviously somebody in the know and somebody with more than just illusory power at the Italian club, so his word should be taken fairly seriously.
"The risk of losing the player is there, but we as a club are prepared for any eventuality. There is nothing, however [to report at the moment]. The player has renewed his contract and is happy here, plus there is a very high clause.
"We are prepared for a possible replacement, if someone pays the clause."
-Vincenzo Guerini; source: Sky Italia via Inside Futbol
The player he's talking about is Juan Cuadrado of course, and said buyout clause is rumored to be a meaty €35m. So if Chelsea truly want the winger, they'll have to pony up all the bags of money required to meet the clause. Otherwise, Cuadrado stays. Simple enough, I suppose.