NSW cop bitter Origin blow with some sad news about one of the Blues' biggest stars just hours before game two kicks off

Penrith will hold Nathan Cleary back until after State of Origin III, with the three-time defending NRL premiers eying off a round-20 return against the Dolphins.

Cleary is now six-and-a-half weeks on from his second hamstring tear of the season, which was initially expected to rule him out for eight weeks.

The superstar No.7 is back running, but is still some way from training with the main group and yet to hit full speed in his rehabilitation.

Penrith have North Queensland on Sunday before facing Brisbane in round 18, but have a well timed round-19 bye before the Dolphins clash.

And coach Ivan Cleary confirmed his son would not return before that bye, with most likely comeback date being at BlueBet Stadium on July 21.

The return date also means the first-choice NSW No.7 is no chance of featuring in Origin III at Suncorp on July 17, ruling him out of the entire series.

'We are hopeful of [him returning] after our next bye,' Cleary said.

'That was a fairly loose target, it hasn't been confirmed.

'He is steadily going through his rehab, going well....he's running, but he is a fair bit off hitting top speed and doing everything with the team.'

Penrith have delved deeper into the 26-year-old's hamstring issues, after he was also missed six games last year with a tear in his right one.

The two-time Clive Churchill Medallist then felt issues in his left hamstring in round three of this season, ruling him out for four weeks.

He was then rested out of another game immediately after through a short turnaround, before going down again with another left hamstring injury in early May.

'The last thing we want is another injury,' the Panthers coach said.

'We've probably done more, this time looking around with the things we can find.

'I'm really comfortable with the approach we've taken and very confident he'll be fine.'

The NSW Blues take on the Queensland Maroons in game two at the MCG on Wednesday night from 8.05pm AEDT.