Either Dane Haylett-Petty or Matt Toomua could join Michael Hooper on a Japan sabbatical, but not both, in a deal worked out with Rugby Australia and the Melbourne Rebels.
RA announced on Wednesday that Wallabies skipper Hooper would take up a six-month playing deal in Japan in 2021 to top up his current contract, which was hit hard with a 30 per cent cut in the COVID-19 interim player pay agreement in April.
It means that the NSW Waratahs will be without their biggest star for most of the next Super Rugby competition, with Hooper, who has 99 Test caps, to return in time for next year's internationals.
The same deal has been offered to a select group of Australian players, including fullback Haylett-Petty, who has played 33 Tests, and playmaker Toomua (47).
Rebels coach Dave Wessels said he had been in discussions with the pair about their plans.
He said it was agreed that they both wouldn't go in 2021.
"The way it works is that both of them can't go together so if one did decide to go, they'd have to alternate years," Wessels said on Thursday.
"Both of them are pretty big parts of our team and both of them are pretty committed to staying at this stage and we're obviously hopeful it plays out that way.
"But I think dependent where things end up with the pay deal going forward they may have to make have to make other decisions.
"If they did decide to make a change for a few months then we'd understand that."
He said he was torn about the model of the agreement, which rewards veteran players, given the impact on the Rebels.
"It's a hard one for me because I want those players to be part of our group. Dane's our regular captain and when he's not playing Matt is the captain so I want to keep both of those guys."
Rugby Union Players' Association (RUPA) boss Justin Harrison said it was a way to reward players and still keep them in Australia.
"What we're seeing is an innovative approach to player contracting and this is a pragmatic solution for the game in Australia both at a club and national level," Harrison said.