ST KILDA captain Nick Riewoldt should not make an "emotional decision" about his playing future following his latest concussion, Brisbane Lions champion Jonathan Brown says.

The 32-year-old spent a night in hospital after being knocked out in a first-quarter head clash with Adelaide's Brodie Smith in the Saints' 46-point loss last Saturday.

Brown, who suffered multiple head injuries over his 256-game career with the Lions, said Riewoldt should take a similar approach to what he did when weighing up his future.

"I didn't speak to anyone apart from my wife for about four days, I didn’t watch TV, I just had a real clear thought in my head and I was able to come to the conclusion (to retire)," Brown told Fox Footy on Monday night.

"I really felt the strain of that and 'Rooey' (Riewoldt) needs to not make an emotional decision.

"He needs all the dust to settle … all the heat that'll be on throughout the week and just get away, really consult his family and think about what he wants going forward."

Brown announced his immediate retirement from the game last June after suffering multiple concussions over his 15-year career, with the final head knock occurring against Greater Western Sydney in round 13.

Riewoldt has also endured a spate of collisions, including one with Adelaide's Graham Johncock in round six, 2011 followed by another clash with North Melbourne's Jack Ziebell in round 23 that year.

Last season, he collided with Carlton's Marc Murphy in round eight, before landing awkwardly in round 14 against West Coast.

Brown said Riewoldt must take the medical staff's advice on board, having endured a similar experience during his time at the Lions.

"It's important that he relies heavily on the doctors; the doctors know him really well," he said.

"They can give him advice as to whether they've seen any changes in the way he recovers from concussions (and) whether he's had any lingering effects after that.

"Eventually it was an easier decision (to retire) when I sat back in the clear light of day because the doctors were very forceful on it that I had to give it away."