Smedts' injury adds to the Cats' injury toll, which includes Nathan Vardy (knee – season), Allen Christensen (back – 8-10 weeks ), Steven Motlop (knee tendinitis – four weeks) and George Burbury (jaw – four weeks).
Skipper Joel Selwood (hamstring) is also in some doubt to play in round one.
Cats football manager Neil Balme confirmed Smedts injured his leg in the club's practice match against North Melbourne last Friday night
"He copped a bit of a whack and it's a bit of bone bruising more than anything else, so it's just a bit sore," Balme told AFL.com.au.
"He'll miss a couple of weeks, which is a bit sad for him, but it's not too serious, fortunately."
Smedts has been using crutches, at certain stages during the day, to help take the weight off his sore leg.
The 21-year-old had been morphed into playing a small defender's role during the NAB Challenge, after spending the bulk of last year as a defensive forward.
He performed solidly against North Melbourne in the club's practice match last Friday night, taking some strong intercept marks before leaving the field with injury.
With Taylor Hunt likely to mind the opposition's most dangerous small forward, Smedts' injury opens the door for second-year defender Jackson Thurlow to take his chance.
"Jackson, particularly, and a few other blokes have always been in the mix. We've never been set on what we're going to do," Balme said.
"But to be frank Billie was probably more likely to be in, than not. So it does provide an opportunity for someone else."
Balme said Selwood was "very confident, he'll be fine" to take his place against the Crows.
Adelaide will also be missing Richard Douglas, Andy Otten, Tom Lynch, Ricky Henderson, Nathan Van Berlo, Taylor Walker, Brent Reilly and Rory Laird from its first-choice side for the clash with the Cats.
Twitter: @AFL_BenGuthrie
