User blog comment:Xilinoc/Ch. 547 - Peace from Shadows/@comment-8669536-20130904133657/@comment-4207271-20130910100742

As Shinigami still retain their Shikai after loosing their Bankai to those medallions, I think it just steals the power and replicates the associated abilities of the Bankai, leaving the spirit intact, but so weakened that they cannot communicate, as if the spirit were taken, then how would the Zanpakuto retain it's Shikai abilities? Or it could partially "reset" the spirit, stealing it's power and memories of how to use Bankai.

However, if I'm wrong here, and the spirit is taken, then Shunsui would likely become a more deadly fighter without Katen Kyokotsu hindering his abilities, he could just go full power at the start.

Either way, this will be very interesting.