Young defender Riley Grundy injured his knee during Saturday's under 23 trial game.

PORT ADELAIDE defender Riley Grundy will miss the start of the season after undergoing surgery to repair the cartilage in his knee.

Grundy landed awkwardly on his right leg after colliding with an opponent during the club’s Under 23 Showdown win over Adelaide on Saturday.

The 19-year-old limped from the ground in the last quarter of the six-point victory and scans confirmed the defender had damaged the lateral meniscus in his right knee.

“It’s disappointing for Riley, who has put together a really solid block of training in pre-season,” said Port Adelaide’s Head of Medical Services, Tim O’Leary.

“Unfortunately, this surgery will delay the start to his season, but we’ll know more about the timeframe for his return to training over the coming weeks.”

SANFL recruit Sean Samblich also suffered a knee injury during the same game.

Scans have confirmed the 26-year-old ruptured the anterior cruciate ligament in his right knee, which will require surgery and sideline him for the 2020 season.

Samblich was this season recruited from Sturt, where he had previously featured in seven league games.