Nathan Cleary given nightmare diagnosis in shocking setback for NSW and the Panthers

 Cleary will likely miss entire State of Origin series Panthers halfback has a grade two hamstring tear Will spend at least eight weeks on the sidelines

NSW halfback Nathan Cleary will likely miss the entire State of Origin series after scans confirmed a grade two hamstring injury that will sideline him for eight weeks.

The champion Penrith playmaker re-injured his right hamstring in Penrith's 16-10 win over Canterbury on Friday night in a devastating blow for the Blues, who have a number of key players sidelined through injury.

Cleary left the field just before half-time after hurting the hamstring for a second time is as many months, with the Panthers issuing a statement on Sunday confirming the diagnosis.

'Scans revealed a grade 2 hamstring tear which will see Cleary ruled out for eight weeks,' the club said in a statement.

Nathan Cleary will likely miss the entire State of Origin after injuring his hamstring

The champion playmaker has suffered a grade two injury tear to his hamstring

It means Cleary is set to miss Origin I at Accor Stadium in Sydney on June 5 and the second game at the MCG on June 26 while he's no certainty to be available for game three in Brisbane on July 17.

Cleary would have been a certain selection for new NSW coach Michael Maguire, while another Blues halves option Nicho Hynes sat out Cronulla's win over Melbourne on Saturday night with a calf injury.

The Sharks said it was more of a precautionary move and they were hopeful he would be available for their Magic Round clash with the Sydney Roosters on Saturday night in Brisbane.

'We haven't had a great deal of time to assess it but I'd suggest it's not significant though so he's a good chance (for next week),' Sharks coach Craig Fitzgibbon said post-match.

Mitch Moses would ordinarily be the frontrunner to replace two-time Clive Churchill medallist Cleary, but the Parramatta playmaker has his own injury woes.

Moses may return from a foot injury against Melbourne next Sunday, but is far from a certainty to play.

Meanwhile, Manly and Blues backline gun Tom Trbojevic is also expected to be unavailable for seven weeks with a hamstring injury.

Cleary will be sidelined for at least eight weeks and likely miss all three Origin games

While Cleary tweaking his hamstring will prove to be dire for the NSW Blues ahead of the State of Origin series opener on June 5, Penrith coach Ivan Cleary declared the 'show goes on.'

'He's pretty shattered actually, it's very disappointing for him. Obviously I'm torn between being his coach and his Dad right now,' the Panthers coach said in the post-match press conference on Friday.

'I thought in that first half he was really starting to come into his own. But yeah anyway, the show goes on.

'He sort of did it sprinting on a kick and diving....'He [then] felt it straight away so he knew, that would suggest it's decent.'