James Courtney has admitted Team Sydney not honouring a “big commitment” led to his sudden departure from the expanded Holden squad, with the 2010 Supercars champion eyeing a return to the series this season.

Courtney shocked the category on Saturday with a short release confirming his immediate exit from the team, which is headed by friend and former Bathurst 1000 winner Jonathan Webb.

It came just a week after he rolled out for the team at the season-opening Superloop Adelaide 500, where he recorded a DNF and 15th-place finish across the two races.

Saturday’s news marked another chapter in a whirlwind few months for the 39-year-old, who left behind a nine-year Walkinshaw Andretti United partnership to pursue the new Tekno Autosports venture.

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THE EXIT: One and done! Supercars bombshell as Courtney quits new team after just ONE race

On the eve of the Adelaide event, Courtney was revealed to have engineered an 11th-hour sponsorship deal for his #19 entry, with Boost Mobile coming on-board.

However, Courtney has since left, and Boost Mobile founder Peter Adderton confirmed his company followed the former series champion out the door.

Team Sydney only confirmed Chris Pither in the second seat at the BP Ultimate SuperTest – just two days prior to first practice in Adelaide.

Speaking on Network Ten’s RPM, Courtney explained why he made the swift exit.

“It was a big commitment that was made in the start, which was a big part of my deal,” Courtney said when asked about why he left.

“I probably let it go on unresolved for too long, because of a friendship with Jon.

“After Adelaide, it became pretty evident it wasn’t going to be honoured. Enough was enough and I had to do what we did.”

'I probably let it go on unresolved for too long.' Pic: Daniel Kalisz

With regards to the team’s development despite being announced last October, Courtney said he “called in a lot of favours to get this to where it was” and admitted to foxsports.com.au he was in for a “tough year”.

However, he nipped it in the bud, and he had support in his corner in order to make his decision.

“Luckily I had great partners in Boost Mobile and Peter Adderton’s support over a long period of time. He was a big part of that,” he said.

“I consulted with those guys right at the end when I was making the decision, and they told me what I should do and that they had my back.

“It’s good. It’s done. Now we can press on and see where the rest of the year’s going to hold.”

Courtney – who has origins in Sydney’s west – conceded had it not been for his attachment to Sydney and his friendship with Webb, he would have walked sooner.

Courtney was pivotal in getting Boost Mobile on-board – but both are gone. Pic: Daniel Kalisz

He also revealed that after he released the statement on Saturday, which was followed by a more detailed social media post, three Supercars teams contacted him about his 2020 plans – of which he harbours a return to the main game, likely in an enduro co-drive.

“I was emotionally very involved. That’s why I probably let it go on as far as I did without pulling it up.

“It is what it is, I wish those guys all the best, Team Sydney, we’ll see how they go. I’ll move on and see what my future holds.

“Unfortunately I put all my eggs in one basket, driving’s all I can do. We’ll be right.

“The crazy thing was, within an hour I had three teams that are in Supercars contacting me about things to be doing this year with those guys.

“Then also other categories. It’s been really interesting to see who has come out of the woodwork.

“I’d like to think that I [will race in Supercars in 2020] … the interest, and what’s been happening over this last 12-hour period, is indicating I will be. I want to.”