PORT Adelaide can stretch a depleted Fremantle defence, but Power coach Ken Hinkley says the key to Saturday's encounter will be to provide his forward line with enough forward 50 entries. 

The Dockers will be without key personnel Luke McPharlin (quad) and Zac Dawson (ankle) for the clash at Adelaide Oval, leaving Clancee Pearce, Alex Silvagni and Lee Spurr as the side's last line of defence.

They'll be forced to contend with in-form Power forwards Jay Schulz, who leads the race for the Coleman Medal, Robbie Gray, Chad Wingard, Angus Monfries and Matt White.

The Power are the second highest scoring side in the competition (805 points) behind Hawthorn (894); Fremantle is ranked seventh (604).

Given the strength of the Dockers' team defence around the ground, Hinkley said that supplying his forwards with opportunities would be difficult.

"First and foremost against Fremantle, one of the biggest challenges you have is getting it in there enough, they're a great side at restricting entries," Hinkley said.

"We need to make sure we provide enough of those entries for our forwards to work because our forwards will present a significant risk to them I'm sure.

"But they won't help us if we don't get the ball inside forward 50."

Aiming to prevent the Power from owning possession will be the Dockers' big-bodied midfield led by the likes of Nat Fyfe and David Mundy.

Hinkley said that in Brad Ebert, Ollie Wines and Travis Boak, Port had the size at ground level to combat its Dockers counterparts, but not to contend with giant ruckman Aaron Sandilands.

"You actually have to play off him (Sandilands) a fair bit, as much as you possibly can and nullify his dominance," he said.

"You watch some of his hit-outs, they can actually go 20m or 30m off his fist which is a big hit.

"I'm not saying we're giving away (the ruck contests), we're going to do our absolute best with Matthew Lobbe to get his hands on the ball."

In disappointing news for the Power, Lobbe's ruck teammate Jarrad Redden will miss the remainder of the season after undergoing a posterior cruciate ligament reconstruction on his left knee on Thursday night.

Redden had the knee operated on in February and had started running unaided but his rehabilitation wasn't progressing as well as was hoped.

Thursday night's reconstruction was the 23-year-old's seventh surgical procedure since June last year when he battled shoulder, hip and knee issues. 

Power high performance manager Darren Burgess said the unlucky ruckman now faced three months of intense rehabilitation.

“This is really disappointing for Jarrad, he’s been working really hard on his rehab but the knee simply hasn’t been progressing as we’d expected,” Burgess said. 

“The aim is for Jarrad to have this surgery now so he can give himself the best chance of doing a full pre-season in preparation for 2015.” 

Twitter: @AFL_Harry