May appeared to run past the ball to charge directly into the Lions player in their match on Saturday, hitting his opponent in the head with his shoulder.

Martin landed flat on his back and was knocked unconscious.

He suffered headaches on Sunday but according to a doctor's report has since passed a concussion test. The club is hopeful, but not certain, that he will be fit to play in its next match.

May pleaded guilty to rough conduct with a severe rating at the AFL tribunal on Tuesday.

The Suns player admitted he could have gone after the ball rather than bumping his opponent – he said it was a split-second decision that he regretted.

After the jury delivered its verdict, May said he felt he had been given a fair hearing. "I'm really disappointed with my actions. I'm hoping Stef's OK," he said.

"Over the next five weeks I'll do everything I can to help out around the club and get myself right to play and I'm looking forward to getting back out there."

During the hearing May said he did not mean to hit Martin high and only realised he had done so when other Brisbane players went after him, pushing and shoving, and he then watched the replay.

May's advocate Tony Burns said Gold Coast captain Gary Ablett had pushed Martin moments before impact, propelling him more quickly forward and worsening the severity of the bump.

Burns said both players were running fast when May decided to bump Martin, and Ablett's push meant Martin could not do anything to protect himself from the bump, saying it was a matter of "physics 101."

But the AFL's lawyer, Jeff Gleeson, said Martin had been running flat out, while May was not – a point the accused player then conceded.

Gleeson said had Martin at that moment leant over to try to scoop up the ball, May would have hit him right on the top of the head, risking a serious spinal injury.

Burns argued that potential injury should have little influence on the jury's considerations, because any on-field contact posed similar risks. But chairman Ross Howie said it was an important point.

Gleeson asked that May be suspended for no less than five weeks, with one game added for his bad record, but another subtracted for his remorse and guilty plea.

Burns asked for four.

Officials previously decided May's bump should be considered careless conduct with severe impact to the head and referred it directly to the tribunal.

In announcing that May would appear at the tribunal, the AFL said May had a bad record and no early plea was available.

In 2015 he served a three-month suspension for a high hit skipper Tom Rockliff, also of the Lions.