The hamstring niggle saw Sio miss the Brumbies' trial game against the NSW Waratahs on February 4 and the loosehead is still unsure if will return against the Crusaders.

"Missing out on the trial match was disappointing because that's my time to get the cobwebs out and unfortunately the next time I'll do that will be in Super Rugby, so I'll have to be on from the get-go," he said.

"Round one is questionable at this stage but we'll see. I think with these sort of niggling hamstring injuries you've just got to take it day by day and it's really going to come down to whether I feel confident or not.

"It's that fine line between pushing yourself to come back because you want to contribute and saying 'maybe I take an extra week' to make sure I can play the rest of the season.

"You're always flirting with that fine line as a rugby player, but this is a professional environment and we're pretty smart with all that here.

"I'm very hopeful and I've made some good steps this week with our great strength and conditioning team here and we'll work together to make the right decision."

Sio started in four of the Wallabies' five spring tour matches and said if he doesn't feature in Christchurch there are plenty of capable replacements at the ready.

"Nic Mayhew has come over, he's had a very good pre-season and Benny Alexander can play either side and Faalelei [Sione] is a young talent, he's very raw at the moment but if we can cultivate some of his talent he has a lot of potential," he said.

"Depth will always get tested, we've lost Tomas [Cubelli] and Lausii [Taliauli] already, that's part of rugby unfortunately, it's tough but you've got to deal with it year-in, year-out.

"I'm excited for the year and I'm looking forward to mixing it with the new boys. Pre-season has been tough but there's been some great skill on show and now I just can't wait get amongst it."

With more than 500 Super Rugby caps exiting stage left at the Brumbies last season, including David Pocock and Stephen Moore, Sio said it's time for the senior players to step up.

"As an experienced player I definitely have to keep the standards up and I guess you work your way into those leadership positions. But if they do arise earlier than you expect than you just have to be ready for it," he said.

"This is one of those years where it's a unique situation where we have lost so many players in leadership roles, which means certain guys have to step up as you see with Sam Carter becoming captain."

Jarrad Butler will likely fill Pocock's No.7 jersey in round one but the lose forward said he wasn't feeling the pressure to replace one of the world's best flankers.

"It's always nice to have Poey running around so to have him not here this year is a shame, but I don't think it's a pressure thing. We've got real depth at the moment, particularly in the back row, and I don't know what they're going to do selection-wise but whoever gets picked will rip in," Butler said.