Head coach Joe Schmidt says Jonathan Sexton is fully fit ahead of Ireland's Six Nations opener against Wales.
Sexton suffered a string of concussions in 2014, leading to an enforced break from the game.
A blow to the head in Leinster's European Champions Cup loss to Wasps last weekend prompted renewed concern over Sexton's long-term health and suggestions from some pundits the influential 30-year-old fly-half should consider retiring.
Yet speaking at the official launch of the Six Nations on Wednesday, Schmidt said: "Johnny trained really well yesterday, he's fully fit and ready to go.
"He's passed his three [head injury assessments], so that's the protocol. It was this time last year that the problem really arose and he had the break.
"Since that time he hasn't really had too many problems. So as far as we're concerned and as far as Johnny's concerned he's very keen to be ready to go in 11 days' time. I think he's good to go."
Schmidt made it clear Ireland have not taken the issue lightly.
"We try to treat head injuries with the respect they need," he added. "That's why he [Sexton] didn’t go back on to the pitch against Wasps on the weekend.
"All we can do is go on the best medical opinion. When they [the experts] give him the all-clear then we have got a lot of trust in them. You know they are the experts."
Reigning Six Nations champions Ireland host Wales next Sunday.