For a bloke who merely "dabbled in league", Wallaby Ryan Cross still couldn't escape reminders of the 13-man-a-side code.

Cross, 28, was celebrating what he thinks will be the biggest moment since his switch two years ago after being named in the starting XV for the Wallabies' Tri-Nations decider against New Zealand at Brisbane on Saturday night.

But the league references still hovered.

He replaced the dumped Timana Tahu - another league convert.

Then Cross admitted he had a friendly wager with Wallabies teammate Lote Tuqiri - yep, a former leaguie - on the outcome of Friday night's NRL finals clash between their respective ex-teams, Brisbane and the Sydney Roosters.

And it was not lost that Cross' Tri-Nations call-up was the biggest Test since his first NRL grand final for the Roosters - the 2000 decider won by Tuqiri's Broncos.

Even Cross couldn't give a definitive answer when asked if rugby had always been his passion when asked.

But Wallabies coach Robbie Deans painted a very different picture.

"The reality is that Ryan is a union player who dabbled in league, not the other way around," he said.

Whatever the case, Cross admitted that the selection was the reason he defected in 2006, ending an eight year "dabble" with league.

Cross will line up with skipper Stirling Mortlock in the centres for a game that will decide the Tri-Nations title and can also keep Australia's hopes alive of Bledisloe Cup glory.

And all in front of a sold-out, 52,000-strong Suncorp Stadium crowd.

"At school I loved playing rugby. It was a huge decision to go to league in the first place (in 1998)," Cross said.

"But I always hoped I would come back, and this is the main reason I came back, playing in these huge games."

Cross came in for Tahu who was axed from the 22-strong squad altogether along with hooker Tatafu Polota-Nau following a record 53-8 loss to South Africa 10 days ago.

"For sure I can sympathise. It's not as easy as everyone thinks (switching codes)," Cross said.

"Unfortunately Timana was caught out in the Test, but I think everyone struggled.

"You do feel for him but in another way it has given me an opportunity and I am looking forward to it."

Cross better make the most of it - Deans made it clear Tahu was hardly on the Wallabies' outer.

"Timana is a player who misses out, people may attempt to make a lot of that, that's their choice," he said.

"But from our perspective, Timana is going to be here for some time.

"Obviously he didn't enjoy his last experience as none of us did, but that was just fuel for the next opportunity that he gets."

But Deans clearly relished pairing Cross with another big, strong centre in Mortlock to combat the likes of New Zealand's Ma'a Nonu.

"I've seen him thrive in the time that he has had this year, he has just grown in stature," he said of Cross.

"He enters this Test knowing that he belongs at this level."

Deans also threw support behind Polota-Nau, replaced by Stephen Moore for the Tri-Nations decider with Adam Freier as his back-up.

Deans also recalled Nathan Sharpe, George Smith and front-rower Al Baxter.

Flanker Richard Brown will make his international debut from the bench.

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