LUCKLESS Sydney premiership defender Alex Johnson has been delisted by the Swans, but may earn a lifeline on the club's rookie list.

Johnson, who has endured five successive knee reconstructions since the 2012 Grand Final, has been told he will not be offered a new contract for 2018.

But the Swans have not rule out redrafting the 25-year-old in the rookie draft. 

The rebounding defender will undergo a series of medical and conditioning assessments in the coming weeks, before a final decision is made ahead of the November 27 rookie draft.

Swans football boss Tom Harley admitted it was a difficult decision, but one based on team balance.

“Alex is an extremely popular and respected member of the playing group, and he has worked incredibly hard to get back to where he is,” Harley said.

“While we know Alex is disappointed, he understands the decision and remains driven to play AFL football.

“We will reassess Alex and our list after the AFL National Draft, however in the interim Alex will continue to train with the team.”

The Swans recruited Johnson with pick 57 in the 2010 NAB AFL Draft, playing 45 games in his first two seasons, including Sydney's premiership win over Hawthorn in 2012.

He ruptured the ACL in his left knee for the first time in a pre-season game against Gold Coast in 2013.

The popular clubman then entered a hellish period in his career, with complications to both his traditional and LARS reconstructions, requiring further surgeries.

After five reconstructions and 1736 days in the sidelines, Johnson made his return to football in the NEAFL in 2017, but was unable to break into the senior team.

The Swans have also informed first-year rookie Sam Fisher that he is no guarantee of retaining his spot on the rookie list next year.

The Canberra product joined the Swans as a category B rookie last year, and will continue to train with the club until the rookie draft at the end of this month.