Sydney Roosters back-up Mitchell Cornish believes Cooper Cronk is the perfect man to help him take the final step in becoming a bona fide NRL halfback.

Cornish will partner Cronk in Saturday’s season-opener against the Wests Tigers should first-choice five-eighth Luke Keary fail to overcome a jaw injury in time to play.

Roosters coach Trent Robinson said Keary would train in the team’s captain’s run on Friday but a final decision won’t be made until game day.

“He’s going really well. He’s had a really good week at training. We’re looking forward to seeing how he progresses,” Robinson told reporters on Friday.

“I’m not obviously a doctor but I know that a plate was inserted which makes it stronger. The bone takes around six weeks to heal and we’re just about at that point now. Pretty close.

“We’ve got one last session today. We’ll see how that goes.”

Cornish, who was named in the No.6 number on Tuesday, played in both the club’s pre-season matches and is adamant he’ll be ready if called on.

“If I get an opportunity, then I’ll take it. I told (Trent), whenever he needs me I’ll be ready and that’s what I plan to do,” Cornish said.

The 25-year-old is in his second year at the Roosters, where he has mostly played as a back-up playmaker since leaving Canberra.

He has yet to play more than six games in a row, and has sat down with Robinson to discuss the areas he needs to improve to become an established halfback.

And now he’s got the former Kangaroos and Queensland State of Origin No.7 to help.

“I’m asking Robbo about it all the time. We’ve worked through some things. It’s more consistency and a bit more dominating the game on big plays,” Cornish said.

“Some games you think, ‘oh yeah, that was sweet.’ Other games you think you could’ve done something else. Learning off blokes like Coops, you learn to take control of moments.”

Robinson on Friday confirmed Cronk would be a definite starter against the Tigers after a minor beach incident during the week.

“He got a cut on his foot at one of his recoveries on Tuesday and he trained yesterday.”