THE BRISBANE Lions have confirmed young defender Sam Skinner has ruptured his left ACL for the second time in just over a year.

Skinner, 19, was poised to debut against Port Adelaide on Saturday night but hyperextended his knee at training on Thursday.

Scans on Friday revealed the worst possible news.

Skinner sustained the same injury playing for Vic Country last June and had only recently made his way back to football via the NEAFL after the Lions took him at pick No.47 in last year's draft.

"Everyone at the club is really hurting for Sam," Lions football manager Matt Francis said.

"He's one of our most professional and dedicated young players.

"It's tough for him now, but he’ll fight back bigger and better."

Skinner has already signed a contract extension until the end of 2018.

Speaking prior to Skinner's scans on Friday morning, coach Justin Leppitsch expressed the club's fears.

"It's a pretty emotional time for Sam and myself and the club after that long rehab," he said.

"You can imagine what it feels like to miss out."