Middleton has explained that players will no longer be able to switch between codes.
Loughborough Lightning's Helena Rowland and Worcester's Alex Matthews had switched back from the short form of the game but Jones has opted to stay with Sevens.
From a performance and comfort point of view it does make a difference … it can be done and hopefully it becomes the norm.
We wanted players to put their hand up in the league and that's why they've been selected accordingly.
The first game against the Black Ferns is on Sunday, 31 October in Exeter.