Stand-in Western Force skipper Sam Wykes admits his team will be rank underdogs in their upcoming two-match rugby tour of Samoa.

With the Force's Wallabies contingent away on Tri-Nations duty, Wykes has been handed the captaincy for the August 20 and 27 hit-outs against Samoa's hard-hitting Test team.

The 23-year-old, who has never captained a side during his rugby career, said he was honoured to receive the role, but conceded the Force - minus a host of stars - would have their backs against the wall on the tour.

Samoa, who notched one of the upsets of world rugby when they defeated the Wallabies 32-23 last month, are expected to field a near full-strength outfit, given the matches against the Force will be their last competitive hit-outs before the World Cup.

"There's no hiding. They're big boys and it's going to be a very physical challenge," Wykes said.

"Against the Wallabies, they were very physical at the breakdown and they've got big, mobile men that can hit hard.

"But the difference for us is we don't have the expectation to go there (and dominate).

"The Wallabies were expected to win that game and win well.

"With us, everyone's expecting us to get flogged.

"But there's definitely a belief that we can go there and win, so everyone's pretty pumped up to play."

Wykes - a 197cm, 109kg lock - enjoyed a breakout Super Rugby season in 2011 and credited his rapid rise to an improved attitude off the field.

"It's definitely taking a more professional approach off-field," Wykes said.

"Training is a given. You've got to train hard on the field and I've always had that work ethic.

"But I guess when I left training, it sort of stopped there. I didn't prepare well off-field as in mentally.

"And that was one of the big things that Rich (coach Richard Graham) challenged me with, and a couple of other people as well.

"That was a really big focus of mine, just knowing my game plan and knowing my role and putting myself in better positions on the field."

Along with their Wallabies stars, the Force will also be without injured key backs Cameron Shepherd,(foot), Gene Fairbanks and Brett Sheehan (knee).

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