Was good off the bench against Japan as well, actually brought a bit of go forward which no one else was offering.
And to be honest, setting aside form, he brings far more of what we need to the table than O'Mahony right now. If we start POM against NZ Stander will be left ineffective, Ruddock would change that. With Conan gone Ruddock is the obvious candidate to fill that void.
O'Mahony has the literally nothing since the All Blacks game last November to justify his presence in the wider squad, let alone the starting team. I understand the arguments to start him but it does reach a point where you need the odd good performance if you want to play for Ireland.