The Waratahs will face an injury-depleted New Zealand rugby side for the second week in a row after Highlanders captain Jimmy Cowan was ruled out of tomorrow night's Super 14 clash in Sydney.

It continues a run of luck for the Australian sides after the Waratahs encountered an under-strength Chiefs last week and the Brumbies downed a Crusaders side missing three stars, including captain Richie McCaw.

Cowan has succumbed to an elbow injury sustained during his side's opening round loss to the Brumbies while All Blacks prop Jamie Mackintosh is out with a knee injury.

That leaves Adam Thompson as the Highlanders only current All Black for the Sydney Football Stadium clash with the unbeaten Waratahs.

The match will kickoff at 8:40pm.