Hamstring tear rules NSW halfback Cleary out of Origin

Nathan Cleary's hopes of featuring in this year's State of Origin series are all but over, scans revealing the NSW halfback has suffered a hamstring tear to leave head coach Brad Fittler with an unwelcome headache.

The Blues No.7 limped out of Penrith's 26-18 win over St George Illawarra on Sunday, with scans on Monday revealing a grade-two tear to his left hamstring.

The injury is set to sideline the playmaker for "up to six weeks", according to the Panthers.

That diagnosis certainly rules him out of the must-win Game II in Brisbane on June 21 and leaves him at long odds to feature in Game III in Sydney on July 12.

There was some welcome news for Fittler on Monday as he contemplates a shake-up to his squad to save the series, with South Sydney lock Cameron Murray cleared of a serious groin injury.

Souths said Murray suffered a low-grade strain and would be monitored throughout the week ahead of their game against the Dragons.

But the more serious concern will be who Fittler brings in as his halfback.

Cleary cut a forlorn figure on the sidelines at BlueBet Stadium on Sunday and Fittler is likely to be experiencing similar feelings as the Blues bid to ambush the Maroons at Suncorp Stadium.

"It's disappointing for him (Cleary) because he loves playing for Penrith, he's a key factor for us performing well," Panthers lock Isaah Yeo said after the Dragons' clash.

"It's the same as Origin, it's disappointing because he's worked so hard on his game.

"That's footy sometimes, you have those unlucky moments.

"But what I do know is that he'll attack his rehab better than anyone."

Cronulla's Nicho Hynes, Parramatta No.7 Mitchell Moses and Brisbane halfback Adam Reynolds are all possible candidates to replace the Penrith man.

All three have experience within the Blues set-up, with Hynes debuting off the bench in last week's series-opening defeat in Adelaide.

Cleary's Penrith and NSW teammate Brian To'o said Hynes could fill the void in Brisbane.

"Clez's job is to direct us and tell us where to go," To'o said.

"Whether he plays or not, I'm sure whoever steps up will get the job done.

"Nicho is definitely someone who takes a lot of pride in playing footy and he can live up to the jersey and do his job for the team."