Cahill has played just 10 minutes of football under his belt in the last 12 weeks after walking out of A-League home Melbourne City for another stint overseas.

He signed with the English club four weeks ago, revelling in the romance of a return to the club he first signed for in 1998.

Cahill, 38, originally said he was leaving City for more game-time in the leadup to the World Cup.

But in his first interview with Australian media since signing for the second-tier club, Cahill moved the goalposts on his intentions.

"I don't think it's about playing. Hundred per cent it's not," Cahill told Fox Sports.

"Everyone says 'oh, you gotta play, gotta play to get to the World Cup'. Lets just put the World Cup aside.

"This is about being in a professional environment that tests me every day. And hopefully, touching wood, no injuries."

It was Cahill who said he needed to play to reach the tournament in Russia, saying exactly that within minutes of Australia reaching the World Cup.

"I need game time ... If I don't (get it at Melbourne City), I'll find a way to play," he said after the Socceroos' playoff qualification triumph over Honduras.

"To get to a World Cup you need to be playing at the highest level."

Under City coach Warren Joyce, Cahill tallied six appearances - and just one start - in the club's opening nine matches of the season; a time when his club participation was limited by his involvement in the qualifying campaign.

Despite Melbourne City enlisting the FFA to help fund an unprecedented wage deal to bring him to the A-League, Cahill believed he was being frozen out and used as a marquee name and not as a player.

Cahill said in his "perfect" first season "everything went to plan" before things came unstuck in season two.

"If you're not part of the plans then you're not part of the plans," he said of his time under Joyce.

"The key thing is whether you are going to be happy to sit there for the rest of the season, say hello to the fans, sign autographs. It's not in my DNA and it never will be."

"(To sign for Millwall) for me is, just amazing."