Sydney have confirmed that the only way co-captain Kieren Jack will play again this season is if they make the AFL grand final.

Scans on Sunday showed that the star midfielder will be out of action for three weeks because of damage to the medial ligament in his left knee.

He is one of several big injury worries for teams going into week one of the finals.

Hawthorn speedster Isaac Smith (knee), Western Bulldogs forward Stewart Crameri (knee and hip), West Coast onballer Chris Masten (hamstring) and Adelaide defender Brodie Smith (ankle) also hurt themselves in round 23.

While there has been plenty of criticism of Fremantle and North Melbourne for resting large groups of players this weekend, those teams came out of their games with no injuries.

Jack suffered his injury in the first quarter of Saturday night’s 63-point win over Gold Coast at the SCG.

It is a major blow for the Swans ahead of Saturday’s qualifying final against Fremantle in Perth.

The good news for Jack is he avoided a more serious knee injury that would have sidelined him for much of next season.

The Swans also expect to regain Jarrad McVeigh (calf) and Nick Smith (hamstring), but star forward Lance Franklin is still regaining touch after returning in the last fortnight from his back injury.

Smith is also likely to be ruled out of Friday night’s qualifying final against West Coast, after he hurt his knee in the third term of the 57-point win on Saturday over Carlton.

The Hawks are yet to confirm the extent of his injury.

They would particularly miss Smith’s run at Domain Stadium, although fellow runner Bradley Hill continued his return to form with a solid game against the Blues.

Hawthorn will regain Cyril Rioli and Luke Breust.

Masten was subbed out during the second term of Saturday night’s 95-point belting of St Kilda and immediately had ice applied to his right hamstring.

Given the protocols around hamstring injuries, he has next to no chance of playing next weekend.

Crameri hurt his hip and knee in Saturday’s upset eight-point loss to Brisbane, which ensured Carlton would finish bottom for the fourth time since 2002.

“Originally I thought something was wrong with the knee, but it seems to be fine,” Crameri told Channel Seven’s Game Day.

“It’s just a bit of a `corky’ and it should be fine by Thursday.”

The Bulldogs will play Adelaide in Saturday’s elimination final at the MCG.

Smith rolled an ankle in the first term of Saturday’s 39-point loss to Geelong, which cost the Crows a home final.

But he is also expected to be fit for next weekend.

In a weekend blighted by dead rubbers, the Tigers beat North by 41 points in a match that had about as much significance as a pre-season hitout.

Next Sunday’s elimination final between the two teams will carry infinitely more weight.

Melbourne beat GWS by 26 points on Sunday at Etihad Stadium.

It is the Demons’ first win at the venue in 23 matches – a losing streak that goes back to 2007.

Essendon ended their dreadful season with a ray of light, beating Collingwood by three points at the MCG.

Heath Hocking kicked a goal with less than two minutes left and the `Dons held on to win 14.11 (95) to 14.8 (92).