Cowboys hooker Rory Kostjasyn was injured against the Storm in Round 10.

The Cowboys appear to have suffered the first significant injury of their premiership defence with coach Paul Green confirming that hooker Rory Kostjasyn suffered a "pretty bad" neck injury in Saturday night's 15-14 loss to the Storm at Suncorp Stadium.

Having started in the hooker position Kostjasyn was forced from the field in the 35th minute on Saturday night after he was caught in an awkward position when trying to make a tackle, Green resigned to being without him for the immediate future.

"His neck's pretty bad," Green said.

"We took him off with the concussion rule but his neck's not great so we'll see how he pulls up but he's pretty sore at the moment.

"He was making a tackle I think. He just got his neck jammed up."

Thankfully for North Queensland Ray Thompson made a successful return from the broken ankle he suffered while in camp with the Indigenous All Stars team with the Townsville Blackhawks in the Intrust Super Cup and would appear to be the logical replacement should Kostjasyn be ruled out.

There was better news for co-captain Matt Scott who despite being troubled by an ankle injury early on Saturday night reiterated – as he did to the bench when it happened – that he was "fine".

Having trailed 12-8 at half-time the Cowboys scored the only try of the second half through a beautifully worked set piece but overall Green was disappointed with their execution, hinting that the week off may have stalled their momentum.

Over the first nine weeks the Cowboys appeared next to impossible to defend but as they were turned away time and again by the best defence in the NRL Green lamented that their composure let them down at crucial times.

"Having the week off can be a good thing, sometimes it's not," Green said of the week off where six players were on representative duty.

"I'm not sure which is the case tonight but we certainly weren't as clinical if you like as what we had been. Sometimes having that break you sometimes lose a bit of that momentum.

"We probably lacked a bit of composure at important times of the game and I think that showed with some of our attack.

"The game was there for us to win at different times but we just lacked a bit of composure at vital times and our execution wasn't as good as what it normally is."

North Queensland had 70 per cent of possession in the opening 20 minutes of the game and only conjured the one try directly from a Storm error and Scott admitted that once momentum turned they struggled to win it back.

"We probably could have capitalised a little better but Melbourne are a very good defensive side," Scott said.

"Tries don't come easy against teams like that. We did the right thing, had good field position, applied some good pressure and then they got a soft try down on our try-line and then another pretty much 100-metre try on the back of it and it took us a little bit too long to swing the momentum back around.

"We started well against them defensively, they tested the ruck out a fair bit but like 'Greeny' said, the game was there for the taking.

"We're pretty disappointed because that's one we let slip through."