A LEADING neurosurgeon says Adelaide star Kurt Tippett should consider "sitting it out for the rest of the year" after suffering his third concussion in five weeks on Saturday.

Professor Jeffrey Rosenfeld, director of neurosurgery at Alfred Hospital in Melbourne, says the Crows forward is risking a more "serious event" if he receives a fourth knock to the head this season.

Labelling it a "compound interest" effect, Professor Rosenfeld has also reignited his suggestion that all athletes employ a three-strikes policy by considering retirement upon their third concussion.

While admitting he's unable to diagnose Tippett from afar, Rosenfeld isn't convinced the Queenslander should play again in 2012, casting serious doubt on the Crows' finals campaign.

"If he's made a full recovery judged by medical people knowledgable in the field of concussion, and they feel that he's made a full recovery, then he can return," Professor Rosenfeld said.

"But it may be with three concussions in the one season that he should have a rest for the rest of the season.

"Repeated concussions are becoming more of a recognised issue, in that more concussions you have, the more possibility there is of having some ongoing symptoms and maybe even permanent problems.

"So you've got to go pretty carefully after three proven concussions.

"You have to give people a chance to recover, it might be a couple of weeks until they really know (how they feel) but he shouldn't be forced back on to the field before he's had a good medical clearance for him to play. Maybe he needs to sit it out for the rest of the year."

Of most concern for Crows medicos is that Tippett - diagnosed with concussion in rounds 13, 15 and 17 - is more susceptible to another concussion should he play Geelong at Simonds Stadium on Saturday.

"The other problem is that if you have more concussions then you are more vulnerable to the next concussion," Professor Rosenfeld said.

"You can have a more serious event if you're knocked on the head again after already having three concussions. If he gets a fourth concussion it may be much worse for him if he hadn't had any concussions at all. It's like a compound interest effect."

Adelaide coach Brenton Sanderson yesterday revealed Tippett is likely to visit a neurosurgeon, specialising in sporting concussions, in Melbourne later this week.

In the most extreme cases, Professor Rosenfeld says all sportspeople - not just footballers - should consider retirement after three concussions.

"We need to develop strong guidelines in this area," Professor Rosenfeld said.

"And it may be if someone has three demonstrated concussions, and has still got ongoing issues from the concussion, then maybe it's time to call it quits.

"Now that's very difficult to say to someone who is earning their living from playing football, basically you're saying you've got to stop earning your living and do something else which is a tough call.

"It's something which needs to be considered for the individual case and it may be that if he's had three severe concussions it might be time for him to say I don't want to risk my brain for the future.

"If someone has had three concussions in a short space of time and they are not making a full recovery then maybe they should at least have time out until they do make a full recovery or they should stop playing and play a less risky sport."

Originally published as Three strikes and out for Tippett