Roosters' Cronk ruled out of Manly clash

The NRL have granted Sydney Roosters approval to bring in Lachlan Lam from outside of their 21-man squad to replace the injured Cooper Cronk.

Sydney Roosters star Cooper Cronk has been ruled out of Saturday's NRL clash with Manly because of a hamstring issue.

The Roosters have drafted in playmaker Lachlan Lam after being granted approval by the NRL to bring him in from outside of their 21-man squad.

It is expected Cronk will miss just one week before returning for the club's round-three match against his former club Melbourne.