But after featuring for Munster A last week the 33-year-old is in the Munster team that will take on Connacht this weekend.
And with less than two months to secure a spot on the plane to Australia Gatland admits that the captain of the 2009 tour to South Africa is still very much in the reckoning.
"The older players with a bit more experience have the upper hand because they have that behind them, don't they?" Gatland told the Irish Examiner.
"We know a lot about Paul O'Connell. We know what he brings to the party so we will be keeping a pretty close eye on him."
Ireland's RBS 6 Nations was decimated by injuries with the likes of O'Connell and Tommy Bowe missing the whole tournament while Simon Zebo, Jonny Sexton and Gordon D'Arcy to name but three, picked up knocks during the Championship.
But Gatland is adamant that players will be given every chance to prove their fitness before making his final decision.
"Someone like Tommy Bowe, if he gets back from injury, Dan Lydiate as well," he added.
"There is a young, talented player in Simon Zebo - is he going to run out of time? We'll keep a close eye on these sort of players over the next six weeks."