MELBOURNE, AUSTRALIA - MARCH 30: Ben Griffiths of the Tigers leaves the field injured during the 2017 AFL round 02 match between the Richmond Tigers and the Collingwood Magpies at the Melbourne Cricket Ground on March 30, 2017 in Melbourne, Australia. (Photo by Michael Willson/AFL Media/Getty Images)

Richmond believe key forward Ben Griffiths will make a positive return to football after concussion problems resulted in him taking an extended leave from the game.

Griffiths was knocked out against Collingwood in round two this season, and didn't play VFL football until a month later, and was concussed in his first game back.

Add those two head knocks to a number of different incidents over the course of his career, and the 25-year-old's career was at the crossroads following his last knock.

The Tigers conceded Griffiths has begun training once again, but has begun with some light training, and has just started some contact work.

“He’s back training now and taking some sort of knocks — obviously not to the head, but to the side and things like that,” Richmond assistant coach Justin Leppitsch told Triple M radio on Monday night.

“So he’s building his confidence in that area. It’s obviously such an unknown, isn’t it, concussion and what happens inside the brain?

“So we’re obviously very mindful of his health as well.”

Richmond will rely on an expert medical opinion before allowing Griffiths to train with the main group, meaning the Tigers are unsure as to when he'll return.

The club has said they will be extremely cautious with his return, meaning Griffiths may not be back until later on this season, or they could even possibly postpone his return until next year.

It's not the first serious case Leppitsch has come across, with the former Brisbane coach thinking back to the retirement of Justin Clarke in 2016.

Clarke suffered a severe concussion in a pre-season training session and was never the same since, and was told by doctors he could never play a contact sport again due to the fear of what another concussion could do to him.

Leppitsch said he hoped Griffiths doesn't succumb to the same fate.

“To watch a boy at the age of 21 lose his career, that was a really hard thing to handle,” Leppitsch said.

“I think we all hope that it doesn’t (end his career), but I don’t think we can categorically say either. There’s so much unknown with the injury.”