Michael Hooper may only return to the Waratahs for the knockout round. Photo: Jeremy Ng/EPA

SYDNEY – Wallabies captain Michael Hooper is expected to miss the New South Wales Waratahs' final three Super Rugby regular season matches as he spends four weeks on the sidelines recovering from a hamstring injury, the team said on Monday.

Hooper limped off with the problem in the Wallabies' 20-16 third test loss to Ireland in Sydney on Saturday and the openside flanker is unlikely to be fully fit until the playoffs.

“Our physios are working with the Wallabies physios around the time frames and from what I understand... at this stage I'd say four weeks,” Waratahs' assistant coach Simon Cron told reporters in Sydney on Monday.

“We'd hope to have him back in our finals series. It's very early. They will keep working through it.”

The Waratahs lead the Australian conference on 35 points, one ahead of the Melbourne Rebels, who they meet in Melbourne on Friday with the result likely to go a long way towards determining the conference winners.

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All three conference winners advance automatically to the eight-team playoffs, with the remaining five places decided on overall points.

The Rebels and Argentina's Jaguares, who are second in the South African conference, currently occupy the seventh and eighth positions in the table, with four New Zealand teams and South Africa's Lions having more points than the Waratahs.

The Sydney-based side also face the Sunwolves in Sydney in their penultimate match before hosting the ACT Brumbies in their final game of the regular season on July 14.

The quarter-finals begin on the weekend of July 20-21.