West Coast forward Josh Kennedy says he would have collapsed on the field against Richmond last week if he didn't take himself off the ground.
Kennedy was initially cleared of concussion and allowed to return to the field after copping an accidental knee to the head from Richmond's Noah Balta in the first quarter.
But within minutes Kennedy knew something was wrong and promptly returned to the bench.
Kennedy was later diagnosed with concussion and was ruled out of Tuesday night's clash with Essendon.
"I was fine for about five minutes and then I came back on thinking I was fine, and then just felt a bit weird," Kennedy told Perth radio station 6PR.
"So I kind of had a bit of delayed concussion and then it went all pear shaped after that for about 30 minutes.
"It was lucky enough I pulled myself off and got over to the boundary because I probably would have collapsed out on the field."
Kennedy has seen close hand the devastating effects concussion can have with his premiership teammate Daniel Venables no certainty to play again after copping a heavy concussion in round nine last year.
The recent revelation that St Kilda great Danny Frawley was suffering from the neurological disorder chronic traumatic encephalopathy at the time of his death last year has also rocked the AFL.
Kennedy said the potentially devastating effects of head knocks was worrying, but he praised the AFL's protocols.
"The game has changed a fair bit in terms of the protocols they go through with concussion now to help prevent things like that," Kennedy said.
"Like tonight, l I'm not allowed to play because of the six, seven-day rule with concussion.
"It's put in place so you do have time to heal and get your brain settled and right before you do go back into a contact situation.
"The rules have been changed to try to protect the head. Sometimes people get frustrated with it.
"But the AFL have put them in place to handle things like this, because we don't want players coming out post career and having head trauma or things going on like Danny Frawley did."