The 25-year-old Waratahs star ruled out retirement, but is uncertain when he will make his return.
He still holds out hope he will be right for Australia's Wold Cup campaign which gets under way in September.
Barnes suffered a heavy concussion in the round two match against the Reds and has not been 100% since.
He has missed several games and was taken from the field during the win over the Highlanders on Saturday after complaining of nausea.
Barnes' absence for the rest of the season is a huge blow to the Waratahs' hopes of claiming a maiden Super Rugby title.
He will also leave a huge hole in the Wallabies' backline if forced out of the World Cup.
We've been working with this for a while and I suppose it's come down to my decision," Barnes said.
"It's probably beneficial, both for myself and the team, that I take some time away from the game and just try and get this thing right."
"I think some of those concussions (he has had four this season), except for maybe the Reds one, was probably footballer's migraine and a lot of the ones I've had in the past fit the same sort of attributes as well.
"It's coming on in waves at the moment. I am having a few more than I usually would have had in the past.
"It's probably time now to try and address it before it becomes too much more of a problem."
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