He has travelled to New Zealand with the squad after returning from a hamstring injury in the VFL at the weekend.
The 31-year-old said he had a challenge to claim a spot in a backline that stood up against the Bombers on Saturday night.
"We've got a few new inclusions in there, which has helped, and they've been pretty solid so far," Fisher said.
"I'll train this week over there … but it's probably hard to fit me in after a good win on the weekend.
"It's more or less been the whole team defence. That's why we've been able to defend better as a back six.
"When the forwards are putting on pressure and the mids are helping out too, it makes our job a lot easier to defend further down the ground."
Fisher has battled back and hamstring issues since early in the pre-season but he was able to play 80 per cent game time in his VFL return.
He said the Saints were travelling across the Tasman confident after their 3-2 start to the year.
"I think it's just the effort and everyone's been playing their role pretty well," he said.
"The mood's always good when we give that effort. That's what we've focused on the wins have come from that.
"As long as we keep playing the style of football we want we know where we can get."
