Fittler heaped the lofty praise on the Brisbane teen giant after selecting him as one of five new faces for Wednesday week's State of Origin opener.

After just 10 NRL games, and despite being banned for the opening four rounds for failing to comply with an NRL integrity unit investigation, he was selected ahead of the likes of Australian Test representative Jordan McLean and Broncos teammate Matt Lodge.

"I coached him as a kid coming through the NSW pathways and I don't know if he's surprised me," Fittler said.

"But he just seems to have aged over the last couple of months while he's played. The game in New Zealand was incredible, he took them on.

"He doesn't look his age. He's mature, he's strong in defence. You couldn't go past him. He seems to be the best front-rower."

Haas hasn't just knocked on the selection door this year, he's kicked it clean off its hinges.

Haas has averaged 167 metres, the third most of any forward in the competition behind Jason Taumalolo (188m) and Blues teammate David Klemmer (171m).

Fittler was himself a teen sensation who made his Origin debut at 18-years-old and knows all too well the pressures that come with an early rise.

Asked if he could remember a more dominant front-rower at that age, Fittler said: "I can't remember a player really.

"He's got his commitment, he's got dedication, he's very focused. He just seems to handle everything in his stride."

Haas will join the side in Sydney on Monday and will have to be carefully managed during the first week of camp because of his observance of Ramadan.

The Muslim tradition ends on June 4, the day before game one, and until then he will not be able to drink and eat between sunrise and sunset.

"I'm sure he's learned how to do it," Fittler said.

"The staff get up pretty early to go for a walk so he'll probably come with us and get something to eat."

Australian Associated Press