As it has been said, it's in the agreement beetween the FFR and clubs, but I think it is the first time (in recent times) that's it's applied by the federation, and surely because of the numerous injuried players already not available at the beginning of the 6N.

Lievremont to preserve the entity of the 23s group as not many spares available if new injuries, cautious only, not the desire to maintain a high physical status IMO.