THE BRISBANE Lions' midfield leaders are not officially on notice, but coach Justin Leppitsch has challenged them to lift against Melbourne on Sunday.

Leppitsch was critical of his midfield in a loss against Port Adelaide two weeks ago and they were even worse in being thumped by Collingwood last Saturday night.

But of the six changes made to take on the Demons at the MCG, only Dayne Beams, who will undergo knee surgery next week, came from the middle of the ground.

Leppitsch said with Beams and captain Tom Rockliff (hamstring) unavailable, it made it difficult to change things too much. 

Although not wanting to mention names, he clearly put the onus on vice-captains Daniel Rich, Pearce Hanley and Dayne Zorko – who was terrific last week – to lift and lead the way.

"We've got a very young crew and some injuries that are mounting and arguably our two best players not playing at the moment through the midfield, so it does leave some holes," Leppitsch said.

"We probably have to challenge our group more in those areas to lift because when our leaders lead well, the rest will follow."

But he stopped short of saying players had been put on notice.

"I probably don't agree with threats, it's not the way I roll," Leppitsch said.

"People know generally whether they've had a good day or a bad day and whether they're on the edge or not. 

"We'll make the changes out of form."

After the disastrous loss to Collingwood, Leppitsch said this week had been about reinforcing to players what they did well.

"You can focus on what we don't do well in life at times, but what does that achieve?

"We've been looking at some of our better games and what we've done well and what our team looks like.

"Time will tell, won't it, whether those actions happen."