I think you guys are laughing too soon. Chelsea specifically do want him next year when Jorginho's contract ends.
By structuring it as a loan, Barca will get Chelsea to pay one year of FdJ's inflated contract (deferred wages). He will give up on the other year's worth of deferred wages I presume. So it's meeting in the middle between the club / player.
If this is an option though I don't understand why we won't be in for it unless the rumors were true and FdJ doesn't want to go to a club that's not in the CL.