The Western Force remain hopeful they’ll be able to retain the services of powerful forward Ben McCalman, but stand-in skipper Sam Wykes has confirmed he’ll be leaving Australian rugby at the end of the Super Rugby season.

Wykes will join winger Nick Cummins at Japanese club Red Sparks, where he has signed a two-year deal.

The 26-year-old told coach Michael Foley of his decision after the Force’s round-one win over the NSW Waratahs, before informing his teammates on Wednesday.

McCalman will also spend time in Japanese club rugby after this year’s World Cup.

However, the 27-year-old won’t be lost to Australian rugby if the ARU grants him one of their new sabbatical contracts.

Under the ARU’s new policies, selected elite players can sign a lucrative one-season deals overseas if they commit long-term to Australian rugby.

The Waratahs are believed to be interested in poaching McCalman in order to replace the departing Wycliff Palu, who will leave for Japan after the World Cup.

But the Force are aiming to lock down McCalman on a long-term deal.

Force fullback Dane Haylett-Petty has re-signed for a further two years, tying him to the Perth-based franchise until the end of 2017.

Wykes was thrust into the Force captaincy role when regular skipper Matt Hodgson tore his hamstring during the pre-season.

The Force started their season with a bonus-point win over the Waratahs, but have since crashed to 13th spot on the back of a six-match losing run.

After this week’s bye, the Force play six of their next eight matches at home, starting with the April 11 clash with the Cheetahs at nib Stadium.