Geelong has confirmed that promising young defender Jackson Thurlow will miss the entire season after tearing his ACL in his right knee.

The 20-year-old underwent scans on Monday, after he was stretched off the ground following a collision with Essendon's Mitch Brown during Saturday afternoon's NAB Challenge match in Shepparton, and will undergo a full knee reconstruction.

โ€œConfirmation that Jackson has torn his ACL is extremely disappointing for him and the club,โ€ Geelong General Manager of Football, Steve Hocking said.

โ€œHis development came along in leaps and bounds last year and he was definitely in the mix to become a permanent member of our back six this season after showing great promise throughout the pre-season.

โ€œAs a club we will ensure he is provided with all the support he needs to work through the process.โ€

Thurlow, who was selected with pick No.16 in the 2012 National Draft, enjoyed a breakout year in 2015, playing 19 senior games for the Cats.