The Broncos enforcer had seemed destined for an early Red Hill exit last month, given permission to negotiate with other clubs despite having a year to run on his NRL contract.
Five rivals, including Wests Tigers, had shown interest in the 25-year-old, who had been relegated to a bench role but wants to start and play big minutes.
Kevin Walters' sudden exit has seemingly torn up that script, Hetherington revealing a phone call from his new coach had him primed to prove himself.
"He seems like a good fella; I think we're in for a tough preseason and I'm looking forward to that, can't wait," Hetherington said ahead of Sunday's PM XIII clash with Papua New Guinea in Port Moresby.
"He's said he wants me to stay ... I never want to leave the Broncos and I'll always have a soft spot for Kev.
"It's on me (to earn a starting spot); if I do all the right things then I've got a good shot at it."
Damien Cook (centre) will lead the PMXIII against Papua New Guinea. (Dave Hunt/AAP PHOTOS)
Fittler will give him a chance to set the tone early.
"(Kobe's a) wonderful player ... he'll have a lot of responsibility," he said, adding that it was important Hetherington left a good impression on potential future teammates.
"It's up to him at the Broncos, if he wants to play more time. In this team he's playing a leading role."
The son of former Queensland and Canterbury star Jason Hetherington is one of the more senior faces in Fittler's squad, captained by Damien Cook.
But the coach expects even they'll have their eyes opened this weekend on a trip that carries extra significance, given the prospect of an NRL team in Papua New Guinea from 2028.
Australia's women, led by Kezie Apps, will also face the host nation.
A strong Australian women's Prime Minister's XIII will take on the hosts in Port Moresby. (Dave Hunt/AAP PHOTOS)
"Most haven't been up there; it'd be a shame if you're a good rugby league player that got to the highest level and never went," he said.
"It's just a different place. It makes you feel very grateful and to understand how much they love the game, it's nice to feel it first hand."
Penrith grand final hero Liam Martin's injury has seen Hudson Young promoted from Fittler's squad to Test duties.
"You always have to be flexible around this time of year, it's a long season," the coach said.
"It's the nature of the game but they're still very keen to represent.
"It's one of those topics, 'Where does rep footy sit in the game?'.
"I think it (PM XIII) is a great concept and it'll last forever and get better and better."
