NORTH Melbourne's defence is wary of West Coast's aerial strength in attack but Roos backman Nathan Grima is confident his side can exploit the tall timber in Sunday's first elimination final at Patersons Stadium.

Grima, who looks set to return to North's team after three weeks on the sidelines with hamstring tendonitis, told kangaroos.com.au on Thursday North had huge respect for the Eagles' tall forwards.

The West Coast attack looks likely to be built around Josh Kennedy (194cm) and Jack Darling (191cm), while Quinten Lynch (192cm) could return from the WAFL after playing 19 of the first 20 games this season.

And just to stretch North's defence even further, the Eagles will rotate ruckmen Dean Cox (203cm) and Nic Naitanui (201cm) regularly through their forward 50.

When the teams last clashed, in round 15 at Blundstone Arena, Cox, in particular, stretched North, taking a game-high six marks inside 50 and kicking 3.1.

But Grima said North's backmen would attempt to play to their strengths - not the Eagles' - on Sunday.

"Obviously, the Eagles forwards will be a massive challenge for us and any time you get a ruckman going forward it's going to be challenging in the air," Grima said ahead of North's Thursday training session.

"But you've got look to exploit them in another way and that might be on the ground.

"Obviously you're always going look at an opponent's strengths but you're going to pick up a weakness or two as well.

"We want to defend them as well as we can, but we want to be able to transition the footy out of the backline as well."

Grima said North's backline had learned some lessons from its two encounters with the Eagles this season, with some match-ups working well and others needing some tinkering.

Grima missed the Eagles' round six victory at Patersons Stadium with a knee injury, but held the hard-running Darling to just seven possessions and two goals in the Eagles' two-point win in round 15.

Grima said he was he was unsure who he'd play on but was confident North would not change the backline structure it had employed for the majority of 2012.

That structure has been built around two key defenders - North has played Grima (192cm), Scott Thompson (193cm) and Luke Delaney (194cm) in the same team just three times this season (rounds eight-10) - with the versatile Michael Firrito (190cm) playing tall when required.

"It's a balancing act. Do you go with an extra tall and compete in the air or do you go with your normal balance and have a bit more run and support at ground level?" Grima said.

"You're never going to get it 100 per cent right but you've got to go with what's worked."

Grima said his left hamstring was feeling "pretty good" after three weeks' rest, while he was also confident his time out the sidelines had not significantly affected his fitness and touch.

"It's obviously not an ideal preparation by any stretch for myself and Daniel [Wells] with his calf," Grima said.

"You're also going to have a few doubts when you've had a few weeks out but once you get in the game and get a few touches, you're away and can slot straight back in.

"If I draw on history there have been times in the past where I've missed a couple of weeks and I've come back and played my best footy."

Nick Bowen covers North Melbourne news for AFL.com.au. Follow him on Twitter: @AFL_Nick