Lowe is a massive loss ahead of Friday night’s knock-out semi-final against the Broncos in Townsville with the 25-year-old suffering the injury in Saturday night's 16-10 semi-final loss to Melbourne.

Lowe has enjoyed a sterling rise in the game in recent seasons, helping the Cowboys to a maiden premiership last year and earning a call-up to the Maroons this year as 18th man. 

Coen Hess, 20, will start in the backrow for Lowe.

Coach Paul Green broke the news at a press conference on Thursday.

"Ethan Lowe's season is finished. Unfortunately he has injured his spinal chord," Green said.

"As you can imagine it is pretty serious and pretty sensitive. Outside of that I can't comment too much.

Green refused to elaborate on the extent of the injury in a sign things are very serious.

"As I said, due to the nature of the injury and the sensitivity surrounding it I am not going to comment any further.”

Lowe is North Queensland’s latest casualty with star winger Antonio Winterstein in massive doubt to feature in Friday night’s match.  

Centre Kane Linnett (hamstring) has also been ruled out and will be replaced by the inexperienced Javid Bowen.

"…At this stage that is not really worth commenting on. We will give Antonio right up to the game to get him right," Green said.

"He is a pretty tough, experienced character. I would hope that he is right."

Kalyn Ponga and Tautau Moga trained with the top squad on Thursday to cover for Winterstein should he fail to overcome injury.