SYDNEY star Tom Papley has undergone post-season knee surgery following a controversial moment in the preliminary final, while the Swans have extended two coaches amid interest from Essendon.

Papley would have missed the Grand Final if the Swans progressed past Fremantle at the SCG on the penultimate weekend of the season.

The 30-year-old was collected low by Dockers defender Karl Worner in an incident that resulted in a grade two medial collateral ligament strain, which would have taken 4-6 weeks to recover from. 

Papley had an arthroscope on his other knee to resolve a lingering problem he carried across September. 

Neither issue will prevent him from being ready for day one of pre-season at the start of December. 

The Swans have also retained assistant coach Amon Buchanan and VFL coach Nick Malceski after Mark McVeigh offered them opportunities to join him at Essendon. 

Both are understood to have signed two-year contracts in recent days. 

McVeigh departed the Swans last month after landing his first full-time coaching gig with the Bombers. 

Essendon has been searching for a range of football department staff and landed the biggest coup of the off-season to date on Monday by signing John Longmire. 

The 2012 premiership coach is moving to the Bombers as GM of football performance to work closely with McVeigh. 

Sydney added Simon Goodwin to Dean Cox's coaching panel last year and aren't expected to replace McVeigh, but will look at adding another development coach to join the club ahead of the start of pre-season. 

Aside from Papley, only captain Callum Mills and young key defender Will Edwards have had surgery in recent months at this stage. 

Edwards is expected to train with the main group later in the pre-season, while Mills is facing up to 12 months on the sidelines after rupturing his ACL in the qualifying final win over Brisbane at the start of the month.