Watson was forced off in the first half of the defeat at the hands of the Tricolours.

Newcastle coach Nathan Brown said the 21-year-old might need to have surgery on his shoulder.

"He's not looking real good," Brown admitted.

"At this stage they're thinking a shoulder op's going to have to happen which would be at least a 12-week injury."

The Knights, undefeated after two rounds, suffered their first loss of the season against Trent Robinson's men.

Brown said his side needs to work on their effort.

"Where we were bad is just some small effort areas," he said.

"If there was a ball on the ground they got it, if they knocked it back from a kick they got it, if it bounced off the legs they got it. When we went through (their line) in the two occasions we passed it to no-one, so not only was our execution not quite good enough but in the effort areas I thought they were a little bit superior.

"With the players they've got we can't afford to let them be better in those areas."