It's an extraordinary scenario but also an illustration of what is possible in modern sport.
Many netballers have returned to the sport after having children but netball's season is much shorter - hockey doesn't really stop - and the travel more limited.
Whitelock didn't know if she would return to top-level hockey after having Addison but the lure of a fourth Olympics proved too hard to resist.
And she has found she can manage it with a baby in tow.
Admittedly, Whitelock is a special player. The 30-year-old has represented New Zealand nearly 250 times and is likely to regain the captaincy.
She is recognised as one of the world's best players and is a shoo-in for Rio selection.
New Zealand Hockey have been supportive in making it work for Whitelock and her child.
"We kept in communication quite early on," she says. "They were looking to try to get me back a little bit earlier but I wasn't ready physically and probably mentally.
"Just the logistical side, they've helped out organising stuff and been a huge help in terms of support.
"They've given me numbers to ring some of the netball girls to see how it works on tour and we just talked about it once we got away."
February's Argentina tour was the perfect opportunity to see if it would work. Whitelock returned fitter and mentally stronger than ever.
The earlier break had allowed her to rehab some ailments and, when she returned to training, she wanted to prove she deserved to be there. She wanted to show you can be a mum and a top-level athlete. She also tested what she needed on tour.
"It was unreal," she says. "Packing started a week earlier. Addison came over with my mum and all the gear. I think I had the least gear ever going on tour and she had everything else. It is tough, but management and Hockey New Zealand have been great in allowing me to take her on tour. She got a bit sick on the way over, which was interesting, but in the end, it was fine.
"We didn't want her to be a distraction. I was more worried about her waking up in the night and waking the rest of the girls, but no one seemed to hear her, except for me of course.
"She travelled well in the end and the girls were really good and enjoyed having a little one around to break up the environment a little bit.
"In terms of game day, we kept Addison away from the group and focused on what we were there to do.
"On rest days, she'd be around and the girls would be straight into her room and playing with her. So I think the girls really enjoyed it, having someone else on tour.
"Addison is pretty easy going. If she was a nightmare, I think I'd struggle to come back. With the family support and the help, that's made it possible.
"There are tough times but it's been good so far."
What has helped is the fact the goal is tangible, with the Rio Olympics starting in three months. New Zealand are ranked fourth, behind the Netherlands, Argentina and Australia, but drew their six-game series in Argentina and won last month's Hawke's Bay eight-nations tournament. They went through that series unbeaten and beat Australia 3-2 in their semifinal.
They came agonisingly close to a medal at the 2012 London Olympics, falling to eventual gold medallists the Netherlands in a penalty shootout in their semifinal before a deflating 3-1 defeat to Great Britain in the bronze medal playoff.
Those events played a part in Whitelock's decision to return. "Just being so close in London, not quite getting that medal," she says.
"That would be a dream, getting a medal in Rio. I was watching the girls and seeing how they were going, and I think they were taking a good step in the right direction and I wanted to be part of it."
