A "FILTHY" Brisbane Lions coach Justin Leppitsch has questioned the rule for taking players from the field on a stretcher, believing a loophole exists that could have cost his team victory against the Sydney Swans on Sunday. 

Leppitsch was furious after Swans ruckman Callum Sinclair hobbled from the Gabba in the final minutes, halting his team's momentum and chance of an upset. 

With the Lions trailing by three points and three minutes remaining, Sinclair was bumped by Darcy Gardiner and crumpled to the ground clutching his knee as the Lions swept the ball forward. 

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As Pearce Hanley and Jarrod McVeigh were contesting a ground ball in the Lions' forward pocket – 120m from Sinclair – umpires stopped play to call for a stretcher.

Without the stretcher in sight, Sinclair hobbled from the ground, and play resumed with a ball-up. 

Leppitsch spoke to officials post-match and was still fuming at his media conference, saying the break in play gave the Swans time to flood the 50. 

"I just don't know how the stretcher call (comes) when there's a live ball in your own forward 50, how the game's allowed to stop," he said. 

"I don't know the ruling behind it, maybe I'm wrong, but my understanding is the play has to stop before the stretcher comes out, not the other way around." 

WATCH: Justin Leppitsch's full media conference 

The AFL would appear to contradict this, with rule 7.3.2 (a) saying "upon being advised or noticing that a Player requires a stretcher, the field Umpire shall stop play at the earliest opportunity". 

The rule then goes on to say that when the ball is in dispute at the time of interruption, play shall resume with a ball up, which it did. 

Callum Sinclair clutches at his knee in the final quarter. Picture: Getty Images 

Leppitsch felt it was a loophole that could be exploited in close games.

"We all saw it, a bloke tripped over his own feet and they called a stretcher," he continued. 

"We're three points down with a live ball in our forward 50 and they can get 18 players down there. 

"Can we use it as a tactic, now, can we? I don't know. 

"I suppose I've asked some questions to get some answers but I'd be highly disappointed if it was used as a tactic when a bloke's gone down with assumedly cramp, after tripping over his own feet, and a runner's called for a stretcher because they're down in numbers late in the game. 

"Wouldn't you be filthy? Of course you would be. 

"I'll get some answers on that, whether it was an error by the officials, or a state of game thing where Sydney took advantage of a rule - I don't know which one it is." 

Swans coach John Longmire said he was unsure of the severity of Sinclair's injury, but expected him to be OK. 

Swans 'good enough' when it counted: Longmire

Leppitsch felt it could have cost his team victory, after the Swans won the ensuing stoppage, marched it downfield and Luke Parker kicked the sealer. 

"Kick a goal down there, it does, doesn't it? "