PORT Adelaide 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 has been forced to undergo further surgery to repair his troublesome knee.

The 23-year-old battled shoulder, hip and knee issues last season and has undergone seven lots of surgery between since last June.

Redden had progressed to running unaided after a knee operation in February, but the knee didn't respond well to the load.

It is unclear how long Redden will be sidelined for, but Hinkley insisted he would return to the AFL.

"He's had a bit of a bad trot, but I'm sure he'll get better, he'll recover and he'll come back and still have a great career," he said.