Playmaker Michael Morgan may be sidelined for a month with a knee injury sustained in Queensland's State of Origin II triumph in Brisbane.
The North Queensland pivot was set to undergo scans but is expected to be sidelined for up to a month after suffering posterior cruciate ligament damage in Wednesday night's 26-16 win over NSW.
That would put him in doubt for Origin III in Sydney on July 13.
He is expected to be officially ruled out of the Cowboys' Monday night home NRL clash with Manly.
Morgan's usual replacement Ray Thompson (knee) is also injured.
It may force Cowboys No.1 Lachlan Coote to move to the halves with youngster Jahrome Hughes slotting in at fullback.
"I am not sure about Morgo, we will just have to wait and see how our physio assesses him," hooker Jake Granville said of Morgan.
"We've got a lot of depth in the club.
"We will prepare as if Morgo is playing but if not we have players who can step up in that role."
North Queensland's NSW prop James Tamou picked up an minor neck complaint and will be monitored ahead of the home clash against the Sea Eagles.
The Cowboys' other Origin stars - the Maroons' Johnathan Thurston, Matt Scott and Justin O'Neill - came through game two unscathed but North Queensland coach Paul Green has not ruled out resting them.
