SEEING a ruckman as Brisbane's medical substitute on Saturday night was unusual, but Chris Fagan says his logic in selecting Darcy Fort as the Lions' 23rd man was simple.

After playing the first 12 games of the season following his off-season move from Geelong, Fort was dropped from the 22 to face St Kilda to accommodate the return of Joe Daniher from shoulder injury.

It meant Oscar McInerney played in the ruck one-out, and Daniher, Eric Hipwood and Dan McStay as a three-pronged forward line.

Although teams usually select smaller, more versatile players as the medi-sub to cover their bases, Fagan said something had been nagging at him in the build-up to facing the Saints.

"I wanted to give you blokes something to talk about, the tallest sub ever," Fagan chuckled following Brisbane's 21-point win.

"I thought our biggest risk with Oscar being the only ruckman, and them having (Paddy) Ryder and (Rowan) Marshall was if something happened to 'O'.

"That could lose us the game fundamentally.

"I made that call this morning (Saturday). I went out for my usual walk. I'd been awake all night thinking about it.

"I thought, why don't we make Darcy Fort the medi-sub? Just in case."

Fagan said Fort could cover any key position injuries – including moving Dan McStay into defence if necessary – and was confident the rest of the Lions had enough versatility to cover elsewhere.

As it turns out, Fort played the final quarter after Brisbane captain Dayne Zorko left the field with a hamstring injury, gathering three disposals and making two tackles in a mix of time between ruck and forward.

Following its bye Brisbane faces Melbourne, whose ruck duo of Max Gawn and Luke Jackson has caused plenty of headaches for opposition teams over the past 18 months.

Will Fagan be tempted to use Fort in the same role again?