Geelong's star recruit Jeremy Cameron will miss at least the initial two games of the AFL season because of a hamstring injury.
The former GWS spearhead, who has a history of hamstring issues, suffered the fresh injury at training on Wednesday.
"Jeremy has started his rehabilitation program but will not be available for at least the opening two rounds," Geelong's general manager of football Simon Lloyd said in a statement on Friday.
Cameron battled hamstring problems while at the Giants which curtailed his output in the 2017 finals and also last season.
The 2019 Coleman medallist also sustained a hamstring injury in January after joining Geelong in a record trade deal.
The Cats traded three first-round draft picks for Cameron - the first time in trade history that three first-rounders were exchanged for a player.
Geelong also gave up a future fourth-round selection for the 27-year-old.
Cameron's latest setback means Geelong won't yet be able to unveil their dream attacking tandem of Cameron and Tom Hawkins, who was last year's Coleman medallist.
"He is a great player and obviously we were preparing to play against him," Adelaide defender Luke Brown told reporters on Friday.
"But Geelong are an experienced side and have a lot of good talls ... we have got to make sure we're on our game."
The Cats, beaten grand finalists last year, will still enter Saturday's Adelaide Oval contest as hot favourites against the Crows, who finished bottom last season.
Cameron's absence has paved the way for Josh Jenkins to play against his former side.
Jenkins only managed one senior game last season after defecting from Adelaide.
"He was a great player for us for a long time and it's good to see him get another opportunity at Geelong," Brown said of Jenkins, who spent eight seasons with the Crows.
"He's a good contested mark and he's mobile as well so it is pretty similar to Cameron."
Geelong's mature-age recruits Isaac Smith (ex-Hawthorn) and Shaun Higgins (ex-Western Bulldogs) will make their debut for the club.
Adelaide will debut two players picked at last year's draft, onballer Sam Berry and goalsneak James Rowe, while midfielder Matt Crouch is out with groin soreness.