Henson has completed a 51-day ban which kept him out of the defeat to England and Sunday's victory over Scotland at the Millennium Stadium.
The 23-year-old - who had been found guilty of elbowing Leicester prop Alex Moreno - is set to make his comeback for the Ospreys in the Celtic League on Friday night.
But Henson will have just 80 minutes to impress Wales coaches Mike Ruddock and Scott Johnson, who insist they will not be selecting anybody for the trip to face Ireland on reputation alone.
"You can only pick on form and he has to play well," said Johnson.
"It is a big ask after so long out but some kids can do it. He is a class player and he may surprise everyone.
"You have to judge him fairly on his performance as a rugby player and nothing else. We will judge him the same way as any other player that is available.
"One great performance for the Ospreys might be enough. He has a chance this week to stake a claim. It is up to Gav to see how he performs, and we will be watching."