Star Fremantle duo Hayden Ballantyne and Michael Walters loom as the key to victory against Port Adelaide if Matthew Pavlich is again ruled out through injury.

Fremantle are sweating on the fitness of skipper Matthew Pavlich as they gear up for their top-four AFL showdown against Port Adelaide on Saturday.

Pavlich was ruled out of last week’s 58-point win over Brisbane after feeling discomfort in his quad just minutes before the start of the match.

The 32-year-old will be further assessed this week, with the Dockers hopeful the injury is only minor.

The winner of Saturday’s clash between Port Adelaide and Fremantle at Perth’s Patersons Stadium will secure fourth spot and the double finals chance that goes with it.

The loser will finish fifth, thrusting them into a sudden-death elimination final against the eighth-placed side.

The latter scenario would prove to be particularly disastrous for Fremantle, whose home-ground advantage would be eroded if arch rivals West Coast sneak into eighth spot.

Star Dockers trio Nat Fyfe (suspended), Michael Barlow (thumb) and Luke McPharlin (calf) have already been ruled out against the Power, while defender Lee Spurr will have to prove his fitness after being subbed out with a tight quad against the Lions.

If Pavlich is ruled out for a second straight game, the heat will be firmly placed on six-game spearhead Matt Taberner, who stood up well against the Lions.

Taberner tallied 22 possessions, 10 marks, six inside-50s and one goal in his finest game to date, with his ability to cover large expanses of ground proving to be a vital asset.

But he is likely to find the going much tougher against a Port Adelaide outfit who returned to form in ruthless fashion during last week’s 103-point demolition of Carlton.

Even if Pavlich is passed fit to play, Fremantle’s small forwards loom as one of the keys to victory.

Hayden Ballantyne and Michael Walters combined for 6.6 against the Lions, while their ability to set up scoring chances for teammates also gave the Lions’ defence all sorts of headaches.

The Power beat Fremantle by 18 points in Adelaide earlier this year, but their recent record against the Dockers in Perth is horrible.

In round 22 last year, the Power copped a 74-point hiding at the hands of Fremantle at Patersons Stadium.

Port haven’t beaten Fremantle in Perth since 2008, with their average losing margin during that four-match run a worrying 53 points.

But in a big boost to the Power, star duo Justin Westhoff (knee) and Jay Schulz (head knock) have been cleared to take on the Dockers.