Fremantle coach Ross Lyon has warned Zac Clarke it’s time to deliver, saying the under-fire ruckman can’t use injury as an excuse for his poor form.

Clarke’s progress has stagnated significantly during the past two years, and the 26-year-old has been dropped for Saturday’s AFL clash with St Kilda at Etihad Stadium.

In five games this season, Clarke has averaged just seven possessions and 14 hit-outs a game.

It’s a far cry from his breakout year of 2013, when he averaged 13 disposals and 21 hit-outs during Fremantle’s charge towards the grand final.

Clarke is out of contract at season’s end, and his future at the club remains up in the air.

The 203cm ruckman has battled knee injuries in recent years, but Lyon says that’s not enough to explain his drop in form.

Clarke will have to prove his worth in the WAFL, and time is running out for him to shine for the Dockers.

“He hasn’t been at his best and he’s disappointed and we’re disappointed,” Lyon said.

“But I still see possibility in Zac. I think we all do – the athleticism.

“We feel like we’ve backed him in and given him opportunities. So he’ll continue to get some opportunity.

“Whether we like it or not, it takes the big guys longer to mature – physically, maybe mentally.

“But it’s the time now we’d like him to start delivering more consistently, there’s no doubt about that.”

Fremantle sit bottom of the table following their horror 0-9 start to 2016.

Lyon has confirmed veteran forward Matthew Pavlich will play against the Saints despite talk he might be rested, while defender Sam Collins will make his AFL debut in one of five changes to the side.

Midfielder Stephen Hill (adductor), Cameron Sutcliffe, Michael Barlow, and Matt de Boer are the other inclusions.

Out of the side goes Alex Pearce (broken leg), Ethan Hughes (calf), David Mundy (calf), Clancee Pearce (concussion) and Clarke.

Hughes, Harley Bennell, Alex Silvagni, Michael Johnson, Mundy, and Shane Yarran have been cut down by calf problems in 2016, and Lyon admits it’s an area the club needs to examine further.

“I’ll get the sea salts on them and hopefully that will fix them,” Lyon joked.

“(Calf injuries) are up across the board in the AFL, but we know we’re above the average.

“Sometimes it’s your whole program (that’s the problem). We’ve done a lot of work. A lot of strength. We’re liaising with experts.”

The Saints replaced Jack Billings (ankle) and Jimmy Webster (illness) with Brodie Murdoch and Jack Sinclair.