Sydney Roosters forward Isaac Liu.

Sydney Roosters forward Isaac Liu has backed New Zealand teammate Dallin Watene-Zelezniak to play against Tonga in a fortnight despite him not playing club football with the Panthers for a month.

Watene-Zelezniak's future at Penrith is expected to be finalised before June 30 but the Kiwis captain is unlikely to feature in another game for the side before the Test squad is announced on June 16.

Kiwis coach Michael Maguire has indicated he will stick with Watene-Zelezniak as captain if he's in the right head space to play, but also conceded the 23-year-old's situation was far from ideal.

Watene-Zelezniak has been training with the Panthers' main squad and reserve grade side in a bid to keep up his fitness levels after he was granted permission by the club to explore his options elsewhere in May.

The St Clair junior won't line up opposite Liu on Sunday at Panthers Stadium but is hopeful he'll run to Mt Smart Stadium on June 22.

"He really led us well last year in those Test matches last year and on tour he was full of voice," Liu told NRL.com.

"He was playing out of his skin at fullback. That will be a decision for Madge but I know I'll be putting my hand up to be a part of the team."

Maguire will have Warriors fullback Roger Tuivasa-Sheck also available which could mean Watene-Zelezniak may shift to the wing. 

Meanwhile, the Roosters' casualty ward has worsened over the past fortnight with Luke Keary ruled out for at least six weeks as a precaution after two head knocks this year.  

Kiwis captain Dallin Watene-Zelezniak.
Kiwis captain Dallin Watene-Zelezniak. ©Grant Trouville/NRL Photos

Prop forward Jared Waerea-Hargreaves will also miss two weeks through suspension as the Tricolours prepare for a brutal representative weekend with Origin II and international matches.

"It's going to test us losing Jared but it gives an opportunity for another player to come in and perform and some leaders in our team to step up," Liu said.

"I think we're in for a testing period but a good test for other players to come in."  

The fitness of Boyd Cordner, Latrell Mitchell and James Tedesco is also expected to be confirmed by Saturday.

Cordner is rated unlikely after picking up an ankle injury, while Mitchell and Tedesco are tipped to play.