Knights co-captain Sione Mata'utia has been ruled out of the World Cup as a precaution.

KNIGHTS co-captain Sione Mata’utia has been denied what might have been his last chance to play alongside his elder brother Peter, after he was ruled out of the rugby league World Cup on Friday on the advice of a neurological expert.

Mata’utia was named in the 24-man Samoan squad on Friday morning, alongside Peter, who announced last week he was parting company with Newcastle.

Knights officials, however, informed coach Toa Samoa Matt Parish that Sione would not be available because of concerns relating to a series of concussions he has suffered over the past two seasons.

They also ruled out new signing Tautau Moga, the former Brisbane centre, who is expected to undergo shoulder surgery.

Newcastle’s physical-performance manager Tony Ayoub confirmed Mata’utia would sit out the tournament but insisted it was “nothing major, just more precautionary”.

The 21-year-old was ordered to stand down against his wishes for Newcastle’s last two games this season after suffering a head knock against Melbourne – his third in the space of a few months.

He also suffered at least two known concussions in 2016.

Since his incident against Melbourne, Mata’utia has undergone a battery of scans and functional assessments.

He visited Melbourne recently to consult with leading neurosurgeon Professor Paul McCrory.

After studying Mata’utia’s results, McCrory advised Newcastle’s staff that he believed the back-rower should be given more recovery time before he resumed playing.

“The area of concussion is just such an unknown in terms of how to treat it,” Ayoub said on Friday.

“Given that Sione still has some minor stuff still ongoing – which is not affecting him, because he doesn’t even know it’s there – just on the advice of the neurologist we decided to give him a bit more time, hence ruling him out of the World Cup.

“In his [McCrory’s] words, it may well have settled already, but let’s just give him another month or two, just to make sure.”

Ayoub said Mata’utia took the news about as well as could be expected.

“There’s no doubt he’s disappointed, but he accepts it,” Ayoub said. “He’s a very smart kid. If it wasn’t quite right, he was always going to sit it out. He’s still got no symptoms, but they’ve found one tiny thing there and the advice was to give him more time.”

Parish brought Dragons centre Tim Lafai and Manly forward Frank Winterstein into his squad to replace Mata’utia and Moga.

 “While it is disappointing, especially at this late stage when we were led to believe both players were fit, I am really delighted that we have such depth to bring in Frank and Tim who were both disappointed not to make the initial squad,” Parish said.

Newcastle have perhaps more cause than any club to tread carefully in relation to concussions.

Former Knights winger James McManus is suing the club in the Supreme Court over a series of concussions that he claims left him with a “traumatic brain injury” and ended his career.

The Knights were also hit with a $50,000 fine this year for failing to take fullback Brendan Elliot from the field for a head-injury assessment after a high tackle. 

Mata’utia, who in 2014 became the youngest-ever Kangaroos representative, admitted in August last year: “I have had two major head knocks and the doctors are being very precautionary.”

Compounding the Knights’ dilemma regarding Mata’utia, he has one season left on his contract and they have reportedly already held preliminary talks about extending his deal.