Bradshaw has been called up to replace him according to the BBC, who are also saying that he is likely to miss the play offs, were we to make it. Think they changed the length of the injury in the article so the story has been updated during the day.
http://www.bbc.com/sport/football/41483358
I'm still half hoping that this is all to scam the Irish preparations and that Gareth will play the second game, but that's just blind optimism.