"I know of a top Serie A club that has been following Ryan since late last season. There's plenty of other interest, too. It might be hard for him to stay at Zwolle beyond this season."
Thomas' contract was recently extended to the end of the 2017-18 season but Zwolle's modest size means a constant recycling of talent is necessary - they offloaded five of their best players in the off-season.
"They will want to keep him, maybe until the summer of 2017, but let's see," says local reporter Herman Nijman, who has covered Zwolle since 2003. "I'm almost certain Ryan was on Ajax's list during summer and, if they need midfielders next season, he will be a prime contender."
It's a heady rise for the kid from Te Puke, who paid his own way to Holland last year for trials with a club he'd never heard of. Even after signing, Thomas expected to spend at least a year in the reserves learning the professional environment.
"Zwolle knew nothing about him - nothing at all," says Nijman. "But both the technical director and head of the youth department received separate tips about him and decided to take a chance on a trial. He made a terrific impression and was training with the first team within a month. That's unusual for an unknown youngster. Normally it would take a year or even two. And after he came into the team he never went out again. That is also very rare. He is young but playing like a guy who is 23 or 24."
Thomas made his debut in late October and played 19 league matches last season, as well as their cup run which climaxed in the stunning 5-1 win over Ajax in Rotterdam.
"That was his final breakthrough," says Grueter. "He had been noticed but after that everybody knew him. It was quite a shock. What was such a boy doing scoring two goals against Ajax?"
"Whatever happens in the future, no one at Zwolle will forget Ryan," says Nijman. "He played a huge role in the first trophy in the history of the club and it will never happen again like it did."
Life has changed quickly for Thomas. Just over a year ago, he was training at Wellington's Ole Academy, playing against Central League clubs and living in a dormitory. Now he has moved into his own apartment and drives a club-sponsored Mercedes A-Class. He has been on the winning side against Ajax (twice), Feyenoord and PSV, recently faced Sparta Prague in the Europa League and is attracting interest from across the continent.
The Eindhoven team fielded World Cup players Memphis Depay, Georginio Wijnaldum (both Holland), Guardado (Mexico) and Santiago Arias (Colombia) but were dismissed 3-1 by the Blauwvingers last week.
"Things couldn't be any better," Thomas says. "I'm loving every minute of it but [long-time coach] Declan [Edge] drummed into us that things can change very fast in football. You have to keep working hard and can't get carried away."
That certainly applies to the prospect of a move to a bigger club.
"It's nice to hear other clubs are interested or want to talk to you," Thomas says. "On the final day of the transfer window, there was talk about Ajax, PSV and FC Twente. But at the moment, Zwolle is perfect for me and I love it here. I don't know what will happen at the end of the season and I can't control the future."
Thomas is wary of second-season syndrome but hopes to turn it into an advantage, as defenders will tend to stand off more, wary of what he can do.
Aside from contributing more in terms of goals and assists, his other focus is to get stronger. He put on 3kg in the past three months - "I'm still a skinny guy but definitely stronger" - to help him cope.
After a year with a foster family, Thomas is now sharing an apartment with fellow Ole graduate Harry Edge, who is in the Zwolle youth team, a few minutes from the city centre. On rare days off, they take day trips to Amsterdam or Rotterdam.
He was disappointed to miss linking with the All Whites during the recent window ("I'd had four games in 10 days and was carrying a few knocks") but is looking forward to the next opportunities against China and Malaysia in November. By then, a few more people might know him.
Thomas has carved another special niche with the sale of signed Zwolle shirts in New Zealand, with the club website announcing it was the first time Zwolle shirts had been on sale outside Holland.
It just remains to be seen how long they can continue to do that.
