Billy Slater has today confirmed he will not play in the opening match of the Holden State of Origin series at the Melbourne Cricket Ground due to a hamstring injury.

"I didn't pull up as well as I would have liked after our training run on Sunday, and because I'm not 100 per cent, it's in my best interests as well as the team's to withdraw from Wednesday's game," Slater said.

Maroons coach Kevin Walters will consult with selectors and senior players before deciding on the final make-up of the side closer to kick off.

He confirmed Anthony Milford and Kalyn Ponga will join the Maroons squad in Melbourne tonight.

"We knew we had some concerns with Billy, but he's a champion player and we needed to give him every chance to play," Walters said.

"We've had plans in place to cover Billy if he didn't come up right, and we've actioned that today with Anthony and Kalyn coming in."