Bernard Foley had concerns that his career may be over during a "scary" struggle with concussion but the Australia fly-half is set to make his Waratahs comeback against Rebels on Friday.
Foley has missed the first five weeks of the Super Rugby season after taking a blow to the head in a trial match against Highlanders.
The playmaker has gone through the return to play protocols and was named in the starting line-up to take on Tony McGahan's side at AAMI Park, but spoke of his doubts over whether he would be able to return.
"It is quite a scary injury because blokes can get knocks and not come back from it," Foley said.
"They can be innocuous or they can be the prone knockout, no-one really knows about this injury. There is no deadline or guidelines to when you are going to be back. I stayed away from Googling it or even watching the movie Concussion.
"I think you have concerns with all that [not being able to return] but you just have to trust the process that you are doing everything in your powers to be right and put yourself in that best position."
Foley said even the most trivial things left him frustrated during his time on the sidelines.
He added: "Just little things that you think 'that doesn't normally annoy me, why is it today?'
"So you'd wake up every day thinking am I going to be right today?"