Few New Zealanders have successfully established themselves so rapidly in Europe. At the same age Ryan Nelsen was still in the American college system, Shane Smeltz was playing in the Australian league and Marco Rojas was one year into his injury plagued stint at VFB Stuttgart.
Thomas was different. He had played fewer than 20 national league matches when he arrived in Zwolle as an teenager, and was expected to spend at least a season in the youth team. But he was promoted to the reserves almost immediately, before making his first team debut a few weeks later.
"Ryan was unusual," says journalist Herman Nijman, who has covered Zwolle since 2003. "He came into the team very quickly and then never went out again. Normally that's not the case with young players, especially with his background."
There are many reasons for his success. He arrived with a strong technical base and Zwolle was the perfect fit. But it all hinges around his mindset. Thomas spent almost eight years being coached by Declan Edge, also living in Edge's house as a boarder, and developed a strong will to succeed.
"The main thing I have learned since I have been a professional is a lot of the time it is just mindset," says Thomas.
"You can be the best player in the world and you can work hard but if you have the wrong mind for the game you are not going to go anywhere. I've seen 50 kids since I have been here that have come through and the trainer is saying 'this guy is the next big thing'.
"He works hard and everything so he looks like a sure thing but in his head he is not right, he can't handle the pressure or can't turn up to training every day. It's about being mentally strong, to cope with the different things that the football world throws at you."
Thomas strives to stay humble, despite being rated as one of the brightest young talents in the Eredivisie, and having two goals in a famous 5-0 Dutch Cup final win over Ajax on his CV.
"There are a few little tricks to it," said Thomas. "Every day you can help pick up all the balls and cones lying around the field after training. I'm never going to be one of those players that goes 'I'm big time, I don't need to do that or this'. It's about mindset and not getting ahead of yourself."
Zwolle have had a topsy-turvy season. They were badly out of sync in the first half of the season, with fears their stay in the top division could be over.
"We lost 3-0 away in our last game before the [winter] break," said Thomas. "We got two red cards, it was possibly the lowest point we could have gone to so to turn it round since then was special."
Zwolle look safe now, and Thomas has played 90 minutes almost every week, as he continues his comeback from dual knee surgeries.
"It was complicated for him," says Nijman. "Without those injury problems he would have been a step further. Now he's getting back to the levels we saw before."
His recent performance in Wellington against Fiji was a reminder to local fans of his class. And he also broke an international scoring duck.
"It was a relief," said Thomas. "I didn't want to be one of those players that ended up playing so many games and not having assists or goals. You think that it doesn't play on your mind, but it does. It's in the back of your mind."
Thomas has settled well in the Netherlands. He's not yet fluent, but his comprehension of Dutch is good and he no longer requires translation on the training pitch . He has a long-term girlfriend, and his parents have relocated from Te Puke to witness their son's European adventures first hand.
Zwolle, a provincial city 115km from Ajax, is a comfortable base - but he may be moving on soon.
"It seems likely he will go to a bigger club," said Nijman. "Most clubs know about him and Ajax were looking at him a while ago. He is one of Zwolle's best assets, that they will be looking to sell at some stage."
Thomas is open to a move, but says first team football is the key; he does not want to be marooned like compatriots Bill Tuiloma and Rojas.
"Who knows what will happen? Things can change quickly," said Thomas.
"If I was injured last year, then I probably wouldn't be at Zwolle right now. You could say it could be at the end of this season, maybe in January. But there is nothing concrete."
