O'Connor could play open or blindside but his physique and style suggest he is more suited to the No 7 jersey.
Kirwan and the Blues scouts were in contact and O'Connor headed north for the 2013 season.
At the moment he sits behind Luke Braid in the openside tussle with the Blues but he is on the bench from where he made his debut last week against the Hurricanes.
"They have got a lot of good loosies in the Crusaders and for me it was the time in my rugby career when I was looking to get as much game time and exposure as I could," he said.
"I was off contract and had to make a decision so the offer came at the right sort of time."
O'Connor thinks the Crusaders will look for territory when they open their campaign tomorrow at Eden Park against the Blues.
"They will also try and play a lot more rugby too. They are under a bit of pressure and may look to play a bit more like Canterbury who have their coaches in there now.
"They can be direct with their forward pack, that is a strength and also look to the edges of the park."