Heading into his last two or three games in a Waratahs jersey, Douglas said he was happy with his decision to sign with Irish club Leinster and hoped to finish off the season with a Super Rugby title-shaped "bang" in a few weeks.

The move abroad will deny the 14-Test cap Wallaby any further Test involvement this year, and in next year's World Cup, but Douglas said the ARU had made the right call.

"I think they have to be strong on their stance and encourage boys to stay and play in Australia, to play for Australia," he said.

"I'd love to [go to the World Cup] but I knew my decision would not allow that and I've come to grips with that."

Douglas and Cummins are good friends. Their fathers, Chris and Mark, travelled together to catch a couple of Wallabies games in Europe at the end of last year, as well as watch Kane's brother Luke play for Scotland in the rugby league World Cup.

Douglas said he respected Cummins' decision to opt out of his second year with the Force and head to Japan.

"He wants to provide for his family and he's got the chance to do that," he said.

"It's not just the money, it's the time he'll get off in the year as well. They'll have a break for three or four months and he'll be able to spend a heap more time with his family.

"Hat's off to him, he's a really good guy and looking after them."

Assuming NSW coach Michael Cheika leaves his second-row pairing unchanged in Brisbane this week, Douglas and Jacques Potgieter will go head to head with experienced Test locking partners Rob Simmons and James Horwill.

While the match is a formality for the minor premiers, Douglas said he was savouring every last minute of football in a Waratahs jersey.

"It would be good to go out with a bang and finish it off. I probably won't get to play with any of these boys for the next few years," he said.

A jarred back he picked up in the side's 44-16 win against the Highlanders on Sunday stopped him training on Tuesday, but it was not expected to rule him out of the match this Saturday.