Hayward broke his left middle finger during a practice match in September shortly before the Oceania championships in Taranaki.
That ruled him out of January's world league final in New Delhi, when the world No 6 Black Sticks achieved their best tier one result - making the final against the Netherlands - since winning the Olympic gold in Montreal in 1976.
"That was absolutely fantastic," Hayward said. "From my personal perspective it was obviously disappointing not to play in it but it's awesome the team is at that level now and can compete against the best in the world.
"That's been the big goal, that when we go to those major tournaments we've got a chance to medal, and it shows where we've come from in the past few years."
Hayward, who has 158 caps, had a wire inserted in his finger as part of the healing process but he's philosophical.
"It was a bit unlucky but in the last four years before that I've been pretty fortunate. It was just my time, I guess."
North Harbour defender Cory Bennett also returns after breaking a thumb on the eve of the World League finals. National coach Colin Batch has named 20 players for the series - and that includes Capital striker Jacob Smith from the national development group - and may well tinker with combinations.
"We have a lot of big events coming up so this will be an excellent opportunity to develop our team during the series," Batch said.
Confidence is up within the squad. The games are important both in their own right but also as leadups for the Champions Challenge in Malaysia in April where New Zealand will be top-ranked.
In turn that leads on to the World Cup in the Hague starting in late May and the Commonwealth Games in Glasgow in July-August.
World No 14 Japan, with a reputation for playing fast, skilful hockey and a team on the rise, will warm up with three games against a New Zealand Invitation XI, starting at Auckland Grammar at noon today, with other games at North Harbour tomorrow night and Sunday at lunchtime.
They should be keenly contested, with several national squad members lining up today.