The Australia international has reportedly signed a letter of intent to join the Waratahs following speculation linking former Wallaby Luke Burgess with the Rebels.
Neither Super Rugby franchise would make official comment on Friday but it is understood the move will be confirmed after round four of the competition
Burgess is seeking early release from his current contract with Toulouse and the Rebels are hot favourites to secure his signature.
The star scrum-half, who won 37 caps before switching to the French club, would be available for a Wallabies comeback in the Rugby Championship, after the series against the Lions.
His return will see him join Phipps and ACT Brumbies' Nic White in the fight to be Queensland half-back Will Genia's back-up at Test level.