"No deal will be made on the next fight until Joseph and his team are satisfied with the final terms and a contract has been fully negotiated and signed.
"We won't be making any further comment for now."
When his next opponent is confirmed, Parker (24-1, 18 KOs) will head back in the ring after losing his WBO title in a unanimous decision loss to Anthony Joshua, the first defeat of his professional career.
He hasn't had a fight in the US since his TKO victory against Keith Thompson early in his career in 2014.
Jennings (23-2, 13 KOs) is coming off four straight wins, his only two losses coming in title fights against Wladimir Klitschko and Luis Ortiz.
The 33-year-old American could be a stern challenge for Parker, with both fighters looking to fight their way towards another shot at the title.