RICHMOND forward Tyrone Vickery has been cleared to play in the Tigers' final NAB Challenge match against Port Adelaide next Thursday.

Worrying footage emerged in Richmond's opening pre-season game against Fremantle two weeks ago of Vickery going up for a mark despite the ball being over 50m away.

The 25-year-old was diagnosed with concussion, but 10 days on, the Tigers are still unsure how he sustained it.

"He has had all the normal tests you would have for concussion and … he has been cleared in all of those," Richmond football manager Dan Richardson told The Age.

"We still don't know exactly what caused it but the doctors have cleared him of any ongoing issues.

"He has recovered fine [and] is back in training. He has not had any symptoms since.

"I would think he would play NAB3 without necessarily having had a lot of discussion about that team yet because we don't play this week."

Vickery had arguably the finest season of his career in 2015, kicking 17 goals in the final five games of the year, including a bag of six against Collingwood in round 21.