Collingwood coach Nathan Buckley says his team's 64-point defeat by Essendon was its worst since the round one demolition by Fremantle, with every player who took the field on Sunday in danger of being dropped.

"Since round one, that's the most disappointed (I've been). Our effort was really poor, our execution was poor, our want and endeavour to stay on task was non-existent, so we've made a massive withdrawal from what we've been trying to build," Buckley said after the game.

"You can put it in a batch with the last four or five weeks (the Pies have lost four of their past five matches) but the players' effort was still there in those games.

"We didn't see this coming, but the last time we had a performance like this in round one, we had two weeks post that and we went away and we came back with some real grit and endeavour and that's clearly what we need right now."

Vote for your top three players from Collingwood's 64-point loss in the Magpie Army Player of the Year Award.

The Magpies lost by 70 points to the Dockers in round one but bounced back to defeat the Sydney Swans at ANZ Stadium the following round as they won eight of their next 10 matches.

After round 12, Collingwood was fourth on the ladder but Sunday's loss saw them slip to eighth on the ladder.

Round 18 is a split round and the Magpies now have two weeks to prepare with their clash against Adelaide at the MCG.

Buckley suggested he would put the acid on his under-performing players during the next fortnight, with some likely to feel the axe at round 18 selection.

"Our personnel will change, there might be two or three or four who will change," Buckley said.

"Some of it will be availability, some of it will be form and basically every one of the players who represented us today, you put yourself in a danger zone in relation to selection no matter who you are, no matter where you've been or what you've done.

"We've supported players in the senior side largely around effort and, as I said, this and the round one game have been the two games where our efforts been really poor.

"We go back and we have a look at who we think is going to come to the party and who's prepared to play their roles and sacrifice for the good of the team."

The Magpies substituted midfielder Clinton Young out of Sunday's game midway through the third term, even though former skipper Nick Maxwell, in his first senior game since round 11, was clearly hampered by an ankle injury he sustained just before half-time.

Buckley said Young had not been injured but defended his decision.

"'Maxy' had notified us that he was right and when you've got a senior player like that who gives you that feedback you trust him," Buckley said.

"He's sore, but structurally he's pretty important to us."

Collingwood spearhead Travis Cloke had an extended stint on the interchange bench during the third quarter, but Buckley said the Magpies had simply not been able to rotate back him onto the field as quickly as they would have liked.

Cloke was held goalless by Bombers defender Cale Hooker, but Buckley defended him when asked if he was one of the players in danger of being dropped.

"Trav has gastro, it's no excuse. He was a little under the weather today," Buckley said.

"I thought his effort was OK early but we didn't help him."