West Coast forward Watt in a coma

The 23-year-old was feeling ill and alerted the team that he was not feeling well shortly after the final whistle sounded in Greymouth.

According to the New Zealand online magazine Stuff, Watt had a blood clot which was causing pressure on his brain. His surgery involved surgeons removing a piece of his skull so they could remove the clot.

He remains in a coma in a critical, but stable condition.

Watt started Saturday's match at openside flanker but was replaced in the second half.

West Coast Rugby Union chief executive Mike Connors said Watt remains in intensive care at Christchurch Hospital with the support of his family.

"All we know is that he is extremely ill in intensive care," he said.

Connors stated they were lucky that it happened so quickly since the St John's paramedics were still at the ground.

"We are just lucky that we had some St John's people there and a physio and some medical people who were able to get him to the hospital very quickly.

"They were just getting ready to go," he added.

After arriving at Grey Base Hospital, he was airlifted to Christchurch Hospital.

"They got the plane over and flew him to Christchurch where he had surgery on Saturday, " he said.

Connors said the substitution had nothing to do with any injuries.

The West Coast Rugby Union, New Zealand Rugby and the New Zealand Rugby Foundation have all offered support to Watt's family.

"It is a time thing really and I don't think the family will know much more until later in the week," Connor said.

Watt made his debut for West Coast in 2015 and has been a regular in the team ever since.

Source: stuff.co.nz