Toomua could be in action as early as Friday night

Star recruit Matt Toomua didn't know how to find his home after training on day one but says he'll be ready for the Melbourne Rebels' Super Rugby clash against the Bulls on Friday night if required.

Due to arrive from England club Leicester next week, Wallabies five-eighth Toomua's return was fast-tracked after Quade Cooper suffered concussion on Friday.

He got a phone call at 9am Sunday, had his flight booked by 11am and by 9pm was on his way to Melbourne and a reunion with cricket star wife Ellyse Perry.

"I came from the airport straight here (to training) and I didn’t know how to get home so I had to go through my emails to find the address as my wife picked out the place we are living in," Toomua said.

Toomua said he would be fit to play if Cooper failed his concussion recovery test, with the biggest challenge adjusting to the Rebels' style of play.

"Fitness-wise I'm ready as I've been going for 30-40 odd weeks now and in terms of time-zone changes, playing international rugby you get used to it," Toomua said.

"The playing style is probably the other thing. The Rebels, they have a bit of a unique playing style so getting used to that will be the biggest challenge."

He said he'd been studying the Melbourne playbook and trying to learn his new teammates' names.

"Jet lag gets you up early so this morning I was going through it all and writing it all down but under pressure we will see how that goes," the 29-year-old said.

"There will be bit of cramming before the final exam if I'm lucky enough, or next week."

Before shifting to the UK, Toomua played 88 matches between 2008 and 2016 for the Brumbies, who are now the Rebels' biggest rivals to top the Australian conference.

He said he was looking forward to a fresh start.

"I’m super excited to be part of a team that is on the rise," Toomua said.

"I enjoy the attacking style - the flatness of the attack is what people talk about and there is depth in the squad as well and hopefully I can help that."

With 40 Test caps, Toomua played five-eighth in the Wallabies' last two Tests of the Europe tour late last year but is taking nothing for granted about national team selection ahead of this year's World Cup.

"There is a lot of 'open' positions and I guess that’s fair enough after the season we had last year," he said.

"There are probably not too many people who can firmly say I will be wearing a starting XV jersey but I’m sure that’s the ambition of everyone else who plays inside centre or winger or whatever."