Carle is in town keeping himself fit with Sydney FC ahead of next month's World Cup qualifiers for the Socceroos and believes that the Jets can make an impact on the league in 2009/10.
He was also confident that the club will sort out the current row over player bonuses that is taking place.
"I hope they all sort it out," he said.
"I really enjoyed my time in Newcastle, I haven't got a bad word to say about the place. I loved my time there.
"I arrived home [Sydney] last Wednesday morning and watched the game [Newcastle versus Beijing Guoan in the ACL] that night. I was struggling with jet-lag, but they managed to keep me up. They played some excellent football, they were absolutely brilliant. They've signed really well, I definitely see them as a threat next season.
"Hopefully, if the on-field performances keep going the way they are then everything else sorts itself out. I just want everyone happy up there because it's such a good place to play, it's such a good club. You only want good things to happen, you don't want to hear the negatives."
Carle said when his time overseas is up he would love to return to the Jets but said ultimately the decision was out of his hands.
"When I do decide to come back, obviously the first phone call will be there [Newcastle]," he said.
"I have a great relationship with Con [Constantine] and [football director] Remo [Nogarotto]. I still keep in touch and I'd love to end up back in Newcastle.
"It's up to them if they want me. I might say I'm ready and they could turn around and 'We don't want you Nicky.' Obviously, then I would have to look elsewhere. But the Jets would be my first preference, for sure."