Ambrose steps down after one championship V8s round

Marco Ambrose of DJR Team Penske with new team owner Roger Penske during the Clipsal 500, Event 01 of the 2015 Australian V8 Supercars Championship Series at the Adelaide Street Circuit.

One championship round.That's how long Marcos Ambrose's V8 Supercars comeback lasted before the ex-champion made the bombshell announcement he would be taking indefinite leave.

And it seems Ambrose sightings this year will be rare despite assurances that he will be back full-time.

Ambrose is expected to only make himself available for this season's three endurance rounds as a co-driver for heavyweight Ford outfit DJR Team Penske after Tuesday's shock call.

Speculation has also linked him to a return to the United States, where he has spent the last nine years on the lucrative NASCAR circuit.

A disillusioned Ambrose appears to have bitten the bullet now to avoid the overwhelming expectation of the next V8 event in his home state Tasmania's Symmons Plains track in a fortnight.

But V8 rivals Lee Holdsworth and Will Davison believe it's far too early for him to take a back seat.Ambrose only contested one championship round before requesting a break, effective immediately, to reassess his comeback - the recent season opener in Adelaide.

And Ambrose made an encouraging V8 return, moving to 12th overall in the championship.But the driver's confidence appeared rattled at the last event, the non-championship round at last weekend's Australian Grand Prix.Ambrose was stuck at the back of the grid for all four races and was involved in a nasty crash at the start of the final 12-lap event.

"He's come home after what's been a massive run of time in America," Mercedes driver Davison told Fox Sports' Inside Supercars.

"He's probably a bit exhausted.

"He's thrown himself in. He probably can't believe how full-on it is out there.

"And I'm surprised. I thought he did really well in Adelaide ...I was pretty impressed.

"And the grand prix, once you qualified where you did, you were stuck there for the weekend anyway."

Holden's Holdsworth believed Ambrose was feeling the pinch early spearheading a one-car team.

"To come back and probably not be as competitive at the grand prix ... it's probably thrown him out a little bit and he's gone 'this is really hard'," he said.

Five-time V8 series champion Mark Skaife was convinced Ambrose would return.

"I think for fans we should be a little patient," he told Fox Sports.

"You don't forget how to drive race cars and Marcos Ambrose is one of the best drivers we have seen in this sport."

Ambrose dominated promotions for the next round in Tasmania where fans were encouraged to "join in the super homecoming".