Adelaide's emerging forward Riley Thilthorpe will miss at least three months of the AFL season because of a knee injury.
Thilthorpe, who had been touted as the Crows' standout performer in the pre-season, suffered a knee injury in the last quarter of Saturday's trial game against West Coast.
After an initial diagnosis of a jarred knee, scans revealed Thilthorpe had torn the lateral meniscus in his left knee.
The 21-year-old had an arthroscopy and then corrective surgery on Wednesday.
"It's obviously very disappointing for Riley and the team," Adelaide's high-performance manager Darren Burgess said.
"He's had a fantastic pre-season and had put in a lot of hard work to put himself in a strong position for the year ahead.
"But now his focus shifts to his rehabilitation and Riley is very diligent when it comes to his training and preparation which will hold him in good stead."
Thilthorpe will have his injured knee in a brace for the next six weeks with Burgess expecting the Crows' highest-ever draft pick - No.2 in 2020 - to return to playing in 12 to 14 weeks.
"Given his age and that he is such a valuable, long-term player for us, we are taking a conservative view with his return to play," Burgess said.
"(We) see him being a significant contributor for the second half of our season."