Newcastle star Kalyn Ponga and Cronulla half Shaun Johnson have been ruled of this weekend's Magic Round fixtures.

Ponga is set to miss multiple weeks with an abductor injury, with Tex Hoy named in his place to face Wests.

Johnson is understood to be sidelined with a minor hamstring injury that was sustained at training earlier this week.

The veteran playmaker will subsequently miss the trip to Queensland to face the Rabbitohs and is likely to miss one to two weeks through the setback.

The injury will further sour Johnson's preparations as he was due to play his 200th NRL game.

Matt Moylan will come into the Sharks' starting side as Johnson joins an extensive injury list at Cronulla.