North Queensland will likely have to overturn a horror record without Johnathan Thurston to keep with the NRL pace-setters and push for a sixth straight finals series.

The Cowboys are set to wait until Monday to find out the extent of Thurston’s right leg injury, however early diagnosis suggests it’s a calf problem.

Thurston was carried up the tunnel in the dying minutes of the Cowboys’ upset 26-16 loss to the Wests Tigers on Saturday night, unable to put any weight on his lower right leg.

The Cowboys face the high-flying St George Illawarra in Wollongong next week, and also have Canterbury and Cronulla in the next five rounds.

Since their finals run began in 2012, the Cowboys have won only three of 13 matches without the Queensland and Australian half.

They lost all three games without him last season, and had a similar winless record in 2014 and 2013.

They are already without star forward Matt Scott for the rest of the season and hooker Jake Granville will miss up to the next month after breaking his leg last week.

Fullback Lachlan Coote has also battled injuries in the early stages of the season.

Youngster Kalyn Ponga could slot into the halves alongside Michael Morgan, while utility Ray Thompson has covered for Thurston previously but is currently injured.

Ben Hampton also played in the halves at Melbourne before moving to Townsville, but is playing hooker in place of Granville.

Thurston was spotted with ice on his lower leg in the sheds on Saturday night, but Cowboys coach Paul Green was unwilling to estimate how long they could be without him for.

“I’m not exactly sure and I don’t want to speculate at the moment,” he said.

“I think it’s calf at this stage so we’ll see how bad it is.”

The injury also threatens to impact on Thurston’s representative swan-song season.

He has just seven-and-a-half weeks to recover for State of Origin opener in Brisbane, while Australia’s Test with New Zealand is less than a month away.

Thurston has not missed a State of Origin match since debuting in 2005, playing a record 36 consecutive matches for Queensland.

The Maroons are already without the leading try-scorer in Origin history, Greg Inglis, and their leading forward in Scott.