Alastair Clarkson concedes North Melbourne ruckman Tristan Xerri is at the mercy of the AFL match review officer after his high hit knocked out Melbourne's Tom Sparrow.
Xerri and St Kilda debutant Max Heath, who caught Sydney's Tom McCartin high with an attempted spoil, face multiple weeks on the sidelines after forcing opponents out of matches.
Carlton's Adam Cerra is also facing a possible suspension in a test case for the league, referred to the tribunal over his latest case of careless umpire contact.
Xerri's attempted tackle on Sparrow caught his opponent high in the immediate follow-up play after a boundary throw-in during Melbourne's 36-point win on Sunday.
Sparrow was knocked out and eventually taken off on a stretcher, and has been put in concussion protocols.
Kangaroos coach Clarkson referenced a separate incident, in which North's Luke Davies-Uniacke was concussed by Western Bulldogs midfielder Ed Richards one week earlier when asked post-match about Xerri's contact.
"We're at (the AFL's) discretion. They'll look at every concussion," Clarkson said.
"But they looked at LDU's concussion last week and said no case to answer, and that's a raised forearm to the scone.
"This is just a tackle ... he's got very, very little time to prepare for the tackle.
"That will be up to the AFL to work out, but unfortunately in the game there's going to be collisions, especially around stoppage and especially around the big rucks."
On debut, St Kilda's Heath forced McCartin out of the Swans' nail-biting five-point win on Sunday with a spoiling attempt that caught his opponent high.
It will likely mean the 204cm ruckman has to wait longer than one week to play his second senior game.
