His hunch skipper Jonathan Brown would be cleared of rough conduct was proven correct on Monday, but Brisbane Lions coach Michael Voss admits he has "no idea" what the AFL's stance is on head-high contact.

The hot topic of the bump again reared its head after Voss all but demanded an explanation of the AFL's policy despite Brown being cleared by the tribunal over an incident with Carlton's Marc Murphy last weekend.

After backing his captain's aggressive approach, Voss turned the tables and wondered aloud what the AFL's head high contact rule was all about.

"There is always room for aggression," Voss said.

"Probably the talk (should be) focused on head high contact - I have no idea what the rule is.

"I don't know whether you get suspended if you hit a guy in the head or you don't.

"If the coaches don't know I don't see how the players could possibly understand what's required regarding head high contact.

"They (AFL) are trying to make it black and white but it is looking very grey again.

Voss cited Carlton's Kade Simpson escaping with a reprimand for a forceful, front on bump on Richmond onballer Daniel Jackson in the season opener.

"You think 'how wasn't that (Simpson incident) looked at?'," Voss said.

"How wasn't that at least put toward the tribunal.

"It was head high contact. It was exactly what had been told to us (that breached the rules).

"But obviously it wasn't deemed sufficient to look at.

"What we need is greater clarity on exactly what the players can or can't do.

"At the moment there isn't any clarity."

Voss added: "As I understand it, if you decide to bump then you put the onus on yourself on where you hit that player.

"If you hit him in the head that means you might be in trouble.

"(But) some guys are getting off when guys get hit (in the head) - I just don't think we have a clear understanding."

Voss said he didn't have a problem with Brown - who has overcome aggression issues in his early years - getting physical with Murphy.

"It's in the spirit of the game, you always want a little bit of contact," Voss said.

"You always want your captain to lead the way.

"I thought he was quite controlled. Throughout the whole game he had a controlled manner about him.

"I don't mind seeing Browny getting aggressive from time to time - as long as he is in control.

"(And) I think he has shown over a long time that he is that (in control)."

Brought to you by AAP © 2024 AAP