Brisbane vice-captain Daniel Merrett admits the Lions’ AFL season goes on the line on Saturday night in their most important Gabba clash in three seasons.

Merrett says the Lions can wave goodbye to any realistic hopes of making the finals if they lose to a surging St Kilda.

The eighth-placed Saints (7-7) are just one game, but five spots, ahead of Brisbane (6-8) who suffered a reality check with last week’s 47-point loss in Sydney.

Brisbane have proven themselves to be a superior team at home but haven’t featured in such a high-stakes game since the 2009 finals series.

“It is a must-win game for us,” Merrett said on Friday.

“Considering where the season’s at, if we win this, it really opens the door for us.

“As players, we realise how big this occasion is and we’re ready for it.

“Obviously, we haven’t been in finals for a couple of years so to have that pressure here on a Saturday night at the Gabba (helps).”

The Lions’ hopes of upsetting St Kilda has been boosted by the timely return of former Saint Matt Maguire who took only a fortnight to overcome an elbow problem expected to sideline him for at least a month.

Maguire’s healing powers ensure Merrett won’t have to return from the forward line to mark up on Justin Koschitzke, with Joel Patfull expected to get the job on Nick Riewoldt.

The Saints have been far more aggressive in their ball movement under coach Scott Watters and their forward line, with Stephen Milne and Adam Schneider also firing, have thrived.

“St Kilda have a very dangerous forward line and (Maguire) is a very important inclusion for us,” Merrett said.

“He’s the ultimate professional. Even on his day off, he was at the club for six hours getting his body right for the weekend so no surprises he’s come back in a couple of weeks early.”

As well as recalling veteran midfielder Simon Black, the Lions have added height through Aaron Cornelius for what looms as a desperate wet-weather affair.

St Kilda are looking for their first back-to-back wins since round three but coach Watters dismissed talk of it being an eight-point game.

“Every game is critical,” Watters said.

“They’re a terrific opponent, particularly here, given they’ve taken some big scalps here so we’ll treat them with a lot of respect.”