INJURY-PRONE Richmond forward Ben Griffiths suffered his second concussion of the season in the VFL on Saturday.

His teammate Jack Riewoldt said earlier this month Griffiths' history with head knocks was "extremely scary", with the big man having suffered more than five throughout his career.

Griffiths, 25, was concussed in round two of this AFL season against Collingwood after landing heavily in a marking contest.

He began wearing a helmet early last season after suffering repeated problems.

"Griffo played in the VFL on the weekend, and he copped another one (concussion) as well," Richmond football manager Neil Balme told 3AW on Monday.

"It's hard work and it's not looking good for him, and we're not quite sure where that will go either.

"We're probably over-conservative but I think that's the way we need to be."

Griffiths has never played more than 16 games in a season since being drafted at No.19 in the NAB AFL Draft in 2009.

Tough Tiger Nick Vlastuin sat out the 13-point win against Melbourne on Anzac Day eve after also having concussion problems.

"He's had two now," Balme said.

"They're almost subjective things, concussions, and that's the hard thing with it. We encourage our doctor to be really conservative with it.

"Five years ago he probably would've played, but he was a little bit tender or ginger after it and he's not quite right, so we didn't even put any sort of pressure on him for him to play.

"Hopefully he'll get up for next week."

Richmond is 5-0 and will fly to Adelaide to face the undefeated Crows on Sunday.