Former Brisbane great Jonathan Brown says Nick Riewoldt should consider his future in the game very carefully after a disturbing head knock on Saturday.

Riewoldt’s sickening clash with Adelaide’s Brodie Smith left the St Kilda star knocked out, and he had to be taken to hospital for observation.

It was the fifth head knock Riewoldt has suffered in the past five years.

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Brown, whose own career was ended due to a spate of nasty head injuries in his final few years, says the end could be approaching for the 32-year-old.

“As a competitor, I’m sure he wants to keep playing footy,” Brown said on Fox Footy’s On the Couch program.

“At the time, I was fighting the battle, I didn’t want to retire, but I started to fail my concussion tests and I also started seeing the emotional impact it was having on my family.

“I also knew it was starting to put pressure on the key decision-makers at my footy club and, more importantly, the doctors.

“When you’re really emotional about it and there’s a lot of commentary around it, like we are doing right now, you feel the strain of that.

“Riewoldt needs to not make an emotional decision. He needs all of the dust to settle, consult his family and think about what he wants going forward.”

Brown said the footage of Riewoldt’s latest knock was confronting.

“The aftermath is what is scaring people … it’s very graphic vision,” Brown said.

“Riewoldt’s actually pulled up pretty well, but the emotions externally are very high at the moment and the emotions internally would be quite high as well, because potentially the family is starting to ask questions.”