FREMANTLE is hopeful over gun ruckman Sean Darcy's ankle injury, but Brandon Walker is set to miss "a fair bit of footy" due to a knee injury.

Darcy and Walker were hurt in the third quarter of the Dockers' 46-point loss to Collingwood at the MCG on Saturday.

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The setbacks added to Freo's recent injury woes and Justin Longmuir's team slumped to a 7-10 record, with its finals chances fading fast.

Walker is set to miss an extended period with his knee injury, while Longmuir was more hopeful over Darcy.

"He (Walker) has done something pretty serious. He's sore. We'll get him back and scan him, but he's going to miss a fair bit of footy I imagine," Longmuir said.

On Darcy, he said: "It was a bit of an innocuous injury, the way it happened, but he's gone over on his ankle so we'll get him back, scan him, hopefully it comes up all right."

The Dockers made a decent start before being blown away by a 10-goal second quarter from the Magpies.

Longmuir said that term, and the game, would be a lesson for some of his young Dockers, including Neil Erasmus, Matt Johnson, Liam Henry and Nathan O'Driscoll. 

"The energy and the speed with which they played with around the midfield in that second quarter was top shelf, top shelf," he said.

"We want to get to that level obviously."

The Pies' second quarter set up another comprehensive victory as they improved to 15-2 and moved three wins clear of third-placed Brisbane.

Collingwood coach Craig McRae said the quarter was close to the best his team can play.

"We want to be exciting to watch and hard to play against," he said.

"I don't like the word perfect ... but that (second quarter) is as close to what our DNA looks like in terms of all facets of our game.

"We had high pressure, we had good contested ball and we won a lot of the territory. There was a lot of stuff there that makes us feel like we're on the right track."