RICHMOND will be without co-captain Toby Nankervis for three weeks after the AFL Tribunal banned him for the brutal bump that left Sydney’s Jake Lloyd concussed.

And star Fremantle midfielder Caleb Serong will join him on the sidelines, failing in his appeal to overturn a one-match ban for a dangerous tackle on Carlton’s Adam Cerra.

The Tribunal found Serong breached his duty of care when rotating Cerra into the ground in their 53-point loss, adding he failed to protect his opponent's head from hitting the turf.

It's a blow for the Dockers, who will be without their gun midfielder for an important clash with Collingwood at the MCG on Saturday where they'll be desperate to win to stay within striking distance of the top eight.

A remorseful Nankervis meanwhile admitted he needed to "be a lot better than that", apologising to Lloyd's family and friends for the high hit.

Tribunal chairwoman Renee Enbom said the ban would have been higher but for Nankervis' "genuine remorse" for the bump in his side's win.

Nankervis offered no defence for his actions and took full responsibility, having apologised to Lloyd immediately after the game in person and via text message a number of days later.

"(I'm) extremely sorry for the position I put Jake in and for his family and friends that watch on," he told the Tribunal.

"As a leader of the football club, I'm accountable and need to be a lot better than that."

The AFL argued for a four-game suspension, saying Richmond was put on notice regarding high contact earlier in the season when Nathan Broad was given four matches for a sling tackle.

Docker Serong pleaded not guilty to his rough conduct charge and additionally challenged the ‘medium' impact grading, arguing Cerra's momentum and him being off balance contributed to the Carlton player's head hitting the ground.

He said he'd tried to protect Cerra by putting himself underneath him to take the impact, adding he needed to keep his arm pinned to stop him getting a handball out, or he "would've been dragged to the bench and been given a spray by the coach".

But AFL counsel Sally Flynn said Serong's tackle was "inherently dangerous" and argued he didn't do enough to satisfy the duty of care, stating Serong made no effort to slow the momentum of the tackle.

Enbom and the jury agreed, finding the tackle had real potential for a head injury despite Cerra walking away unscathed.

"A reasonable player would not regard it as prudent to pin an opponent's arm in the way it was pinned, while rotating the opponent into the ground … there were other options reasonably open to him," she said.

Earlier on Tuesday, Essendon ruckman Andrew Phillips accepted a one-match ban for a high bump on Adelaide's Reilly O'Brien.