Polota-Nau blow for Wallabies

Sydney - Hooker Tatafu Polota-Nau has been ruled out of Australia's Rugby Championship opener against New Zealand with a knee injury suffered in Saturday's Super Rugby final.

Polota-Nau underwent scans on Monday and was found to have a low-grade medial crucial ligament strain.

He limped from the field shortly after half-time on Saturday during the Waratahs' 33-32 win over the Crusaders.

Polota-Nau's injury compounds the Wallabies' front row problems because hooker and captain Stephen Moore has already been ruled out for the remainder of the season with a knee injury.

Nathan Charles, who has played only two Tests, will likely start in place of Polota-Nau against New Zealand at Sydney on August 16.

The All Blacks have won the Rugby Championships the last two years and are unbeaten in their last 17 Tests.