Sale Sharks and Worcester Warriors have been given conditional offers to join the women's Premier 15s next season.
However, Sale will remain in the league as the Rugby Football Union (RFU) wants to maintain women's rugby presence in northern England.
Financially troubled Worcester have recently secured funding to allow them to continue to operate.
Ten teams will compete in the league next season: Leicester and Ealing, who join for the first time, and existing Premier 15s clubs Loughborough, Bristol, Exeter, Gloucester-Hartpury, Harlequins and Saracens.
Alex Teasdale, RFU women's game director, said: "We know rugby in the north can be disproportionately challenged. We have therefore responded to the panel's recommendation to explore if a northern club could be part of the league.
"Given the importance of having a northern provision, we believe with the proposed support package Sale Sharks will be well placed to continue their work to develop and grow rugby in the region."
The RFU said it will continue to work towards a solution for clubs not offered a place, and for those who wish to join the league in the future.
Darlington Mowden Park Sharks and Wasps, the Premier 15s bottom two sides, will not be involved next season.
Following the initial tender, Wasps said they hoped to rejoin "at the earliest possible moment" and that they would move from London to Coventry to be more closely aligned with the men's side.
DMP Sharks, who crowdfunded to stay in the league this term, did not apply to be included next season because of the increased level of investment required.