Welch incidentally smacked his head into Walker's during a tackle while Walker delivered a high kick.
After the match, Roosters coach Trent Robinson slammed the tackle and criticised the officiating after nothing was done by either referee.
"I didn’t like that challenge," Robinson said.
"He kicked the ball and got hit in the head after he kicked the ball.
"I’m sick of talking about Roosters players and head contact, I’m sick of talking about it.
Commentator Greg Alexander said Welch could be in danger of missing the final Origin clash with the tackle likely to catch they eye of the NRl.
The commentators, Alexander and Warren Smith both questioned Welch's duty of care in the tackle.
"The emphasis is on not making contact with the head in any situation but especially so on the kicker," said Smith.
"Duty of care (is) on the man coming forward."
“You’ve got to bend your back and make sure you don’t make contact with the kicker’s head I would have thought, given the emphasis we’ve seen in recent times!”