Newcastle Knights star centre Bradman Best has been ruled out of the opening State of Origin game with a hamstring tear.

Best was taken out of the Knights' game during Magic Round at halftime by coach Adam O'Brien, hoping to limit the damage to his hamstring, but as it turns out, the damage had already been done.

Both News Corp and the Newcastle Herald are reporting that Best has suffered a Grade 2 tear of his hamstring and will need at least four weeks on the sideline, leaving him out of Game 1, and at long odds to play Game 2 if New South Wales Blues coach Michael Maguire was to give him a recall.

"Bradman's obviously disappointed but he has also accepted that it is what it is," Knight football director Peter Parr said according to the Newcastle Herald.

"He knows that injuries are part of football.

"The important thing now for him is to focus on his recovery and get himself back to full fitness.

"Hopefully he can recover in time to put himself in the mix for Origin 2."

It's a devastating blow for the Blues. Best was as good as a walk-up starter for the side after making his Origin debut in Game 3 last year, particularly given other injuries, but will now miss out.

It leaves Maguire in a tricky situation, with the likes of Stephen Crichton and Jesse Ramien now the front-runners for the centre spots, while Matt Burton and Latrell Mitchell could come into calculation.

At the Knights, it means Best will join currently injured fullback Kalyn Ponga on the sideline in an equally large blow to the Hunter-based sides chances this season.