Geelong premiership player Cam Guthrie has suffered what could be a serious quad injury as he tries to bounce back from an interrupted 2023 AFL season.
The midfielder hurt himself in the opening seconds of the Cats' 17-point practice match win against Carlton at Ikon Park on Thursday.
Guthrie left the field after taking the first kick of the contest and did not return for the rest of the match.
"It's a quad, but we don't know the severity of it," Cats assistant coach James Rahilly said.
"I'm sure they'll (medical staff) look at it.
"We'll see what comes of it, but he's had a ripping pre-season.
"He hasn't missed a trick, so we'll see how it plays out."
The 31-year-old was limited to just six games last season because of a toe injury.
Meanwhile, young Cats forward Oliver Dempsey provided the highlight of the match in hot conditions at Carlton's home ground.
Dempsey, who has played seven games across the past two seasons, leapt high in the second quarter to bring down a grab that would have been a mark of the year contender in the home-and-away season.
The 21-year-old went back and comfortably kicked the goal from about 25m out on a slight angle.
Beaten preliminary finalists last year, Carlton put out an under-strength team against the Cats, who were missing the likes of vice-captains Sam Walsh and Jacob Weitering.
Draftee Ashton Moir impressed with two goals, while former Essendon and Port Adelaide forward Orazio Fantasia staked his claim to debut early in his time at a third club.
Star midfielder Walsh did not take on the Cats and has already been ruled out of next week's practice match against Melbourne with a back issue.
Walsh, who won the Gary Ayres Medal as the best player of last year's finals series, missed the first four games of last season after having surgery to fix a bulging disc in his back.
The 23-year-old remains in significant doubt to face the Brisbane Lions in the Blues' opening-round match on March 8.
"There's no actual timeline with Sam, it's milestones he's got to tick," Carlton assistant coach Aaron Hamill said.
"It's just back related, that's as far as we'll go on it ... I reckon that's all the detail we need on it.
"There's a slight issue there in his back ... but he's had an outstanding summer and we expect he'll be fine."
Meanwhile, star Sydney recruit Brodie Grundy made a good first impression as the Swans accounted for rivals GWS by 26 points in their pre-season match.
Grundy, a dual All-Australian at Collingwood, has an opportunity to make the ruck spot his own at the Swans after his partnership with Max Gawn lasted just one season at Melbourne.
"Grundy did some really good things," Swans assistant coach Mark McVeigh said.
"I think we're all excited with what we've seen, not only with his ruck work, but also around the ground."