NSW Waratahs playmaker Bernard Foley says a relapse of his post-concussion symptoms had nothing to do with his Super Rugby return last week.
The Wallabies playmaker has been ruled out of Sunday's clash with the Crusaders after suffering a setback in the days after his starring role against the Melbourne Rebels.
Foley made a series of fearless, body-on-the-line tackles in his comeback game, but defended his and the Waratahs' medical team's decision to play.
"It's been a frustrating week, in terms of symptoms just re-occurring (but) nothing to do with the game last week," Foley told Sky Sports Radio on Friday.
"It's just sort of come back after the game."
Foley said it was unknown when he would make another return. The 27-year-old was initially sidelined for five weeks after copping a head knock in a pre-season trial against the Highlanders last month.
"It's a tough one. Ultimately, I think it is just time," Foley said.
"With the nature of head knocks and concussion, no one really knows.
"It is just time and you know when you feel right, when you're back to normal.
"When it first happened, you think you probably play the next week and it just sort of lingers and you just don't feel 100 per cent for a couple of weeks and it's still ongoing for me."
Despite the uncertainty, Foley said he was "not really worried" about his long-term health.
"Just more frustrated, I suppose, in terms of still sitting on the sideline, still having the symptoms," he said.
"Hopefully it's something that'll clear up in the near future."
Foley said he had investigated osteopathy and vestibular rehabilitation therapy to speed up his recovery.
