"It's not about one player. It's about the whole 17."
It is understood Warriors medical staff recommended that Mannering stay home to complete an extra week of rehab, with the 41-test back-rower due to join the Kiwis next Wednesday before their departure for the UK.
"I've been in contact constantly with the (Warriors) physio there John Love and from all the things I'm hearing it's going well," Kidwell explained.
"It was a decision from the experts, the physio's over there, to leave him there until we can bring him to the UK and that's the main thing.
"We're in communication every day and at this stage, yes, he is coming."
Proctor's selection comes after he was the last to arrive in camp yesterday, having stayed in Melbourne for the birth of his baby early on Monday morning.
"He's buzzing as well. It's always a great achievement and one of the best things in life seeing your kids being born.
"He got the blessing from his lovely wife to come into camp and he's bringing some really good energy."
Alongside captain Jesse Bromwich, Kidwell is relying heavily on Warriors teammates, five-eighth Thomas Leuluai and hooker Issac Luke to help lead the way for the younger members of the Kiwis.
Leuluai will resume his left-edge combination with Warriors centre and Kiwis debutante Solomone Kata, while Luke will be eager to impress after being overlooked for May's Anzac test defeat to Australia in Newcastle.
Front-rower Adam Blair, who co-captained the Kiwis on last year's end of season tour of England, has been relegated to the bench behind Jared Waerea Hargreaves, but is still expected to play a leading role.
"Everyone has got a part to play," said Kidwell. "Adam is part of our leadership group and it's a role he loves and enjoys and he'll be a very important part coming off the bench.
"At times we need to rely on that experience during tough times to keep going.
"It's very important. If you have a look at the Kangaroos they've got some experience as well.
"To have that combination with Thomas and Sol on that side is important too."
Kidwell expects he will experience some butterflies in the lead-up to his first test in charge but is focused on providing his players with the best possible build-up over the next three days.
"I'm feeling pretty relaxed at the moment," he said. "I'm sure as the day gets nearer that there will be a few nerves.
"I've just got to make sure that we've given them the best preparation that we can to get them to perform on Saturday night."