Leuenberger will play his first senior match in almost 12 months on Saturday when he runs out against Adelaide at the Gabba.
The 204cm ruckman injured his Achilles in round three against Fremantle last season and has taken a cautious approach to returning.
After playing a full match in the reserves last weekend, Voss said it was a difficult decision to squeeze him in ahead of teenager Billy Longer.
Longer was outmuscled by Western Bulldog Will Minson in the 68-point round-one loss, but was one of few Lions to make a real effort.
"Billy was doing some good things. That was a tough selection for us," Voss said on Friday.
"But to have 'Leuey' back there, he's like an extra midfielder, he gets around the ground, he's able to win possessions, he spreads really well and he's very good around contests.
"Our expectations are still … he needs to contribute and put his head down and give us a contest and if we get some of those other things, that's a bonus, but we've got to realise he needs a few weeks to get his mojo back."
Voss said he was confident in Leuenberger's fitness after the West Australian completed the majority of the pre-season.
He was one of three inclusions to play the Crows, joined by tagging midfielder Andrew Raines and utility Ryan Lester who came in for Matt Maguire (calf) and Aaron Cornelius (omitted).
Voss said training intensity had lifted this week after the players "expressed their disappointment" following the poor showing against the Bulldogs.
He said the Crows were a top-four calibre team and the Lions had to return to what they did so successfully in winning the NAB Cup.
"Top four sides have good pressure on the ball, move it when they want to and defend well. We're at our home venue and this is a pretty important place for us," Voss said.
"If we want to be manipulated by the opposition then we'll get the same outcome.
"We can't afford for that to happen. We have to put the opposition to the sword from time to time and we just didn't do that at all last week. That's been our focus this week."
Michael Whiting covers Brisbane Lions news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
