(Josh Dascal is a freelance writer, Media and Communications graduate at Melbourne University and BPL contributor.)

It's fair to say the opening round of the new AFL season had pretty much everything: a thrilling draw, a dour game between two powerhouses salvaged by a gripping finish, a fairytale beginning for James Hird's coaching career, and an ominous statement from the defending premiers. 

But the biggest talking point from the weekend will undoubtedly be the league's controversial new substitute rule, which directly or indirectly affected the outcome of several matches. 

Going into round one, there was no shortage of predictions as to the implications of the rule. Some sounded the death knell for the traditional second ruckman (incidentally, only one team - Sydney - used a ruckman as its substitute), while others argued rotations would be limited, in turn slowing the game down. 

It was fitting, then, that the first substitute was invoked less than an hour into the new season, when Jarrad Waite was forced off with mild concussion in Carlton's win over Richmond. 

The AFL drew fire last week when it announced a crackdown on concussed players, with the new law stipulating that any player deemed concussed by their club doctor would be unable to return to the field. In Waite's case, Blues coach Brett Ratten suggested post-match that his tall forward could have played on with little risk after half time. 

His withdrawal arguably shifted the momentum of the match, as Carlton's forward structure collapsed, resulting in a six-goal third term from Richmond that turned the match on its head. 

But remarkably, discussion over Waite's forced substitution was cast aside when Geelong star Joel Selwood was knocked unconscious in a sickening collision with St Kilda's Farren Ray. His substitution was inevitable, and his replacement, Darren Milburn, would kick the winning goal with less than 30 seconds left, securing a gutsy first-up win for new Cats coach Chris Scott. 

Nevertheless, given that the two incidents were poles apart in their relative impacts, we are still none the wiser over the true merits of the new concussion clampdown. While Waite's case highlighted the vagaries of what constitutes concussion, Selwood's exemplified the risks players take when they put their heads over the ball each week. 

The substitute rule was also particularly harsh on the brave Brisbane Lions, who finished their game against Fremantle with no fit players on the bench. While Lions coach Michael Voss had nothing but praise for his players in the face of clear adversity, his decision to substitute struggling debutant Claye Beams was compounded by the losses of Brent Staker and Jonathan Brown, who were forced off with long-term injuries within ten minutes of Beams's departure. 

To exacerbate the Lions' woes, Mitch Clark sustained an unlucky knock to the head, while several of the side's young players cramped up in the compelling last quarter. With these injuries limiting rotations, the Lions were unable to hold on for a famous victory. Whether or not Beams, who whilst injured was clearly in a better state than Staker or Brown, would have been able to return to the field, if only to relieve another player, is uncertain. But the Lions' unlucky run serves to further magnify the impact of the rule. 

Should clubs be able to reinstate a substituted player if hit by an injury crisis? Common sense would suggest yes, but any loosening of the strict interpretation would open the door to manipulation. Brisbane's case, however, certainly makes for compelling evidence. 

Nonetheless, it should be noted that several other teams used the rule to their advantage. Ricky Petterd sparked the Demons during his fourth-quarter cameo in the draw against Sydney, while Collingwood's Brent Macaffer and West Coast's Andrew Gaff benefited from their fresh legs against tiring opposition. 

It's clear that teams are still familiarising themselves with the new rule, and there's no doubt we will be debating its merits throughout the season. But, with Brisbane arguably falling victim to the rule already, only time will tell whether it will affect any more teams that are suddenly beset by injuries during a match.