Whitaker, who turns 31 on October 31, is determined to continue playing a key role for the Wallabies, with selection on the four-Test European Spring Tour in November a priority.
But arguably the most patient player in world rugby said on Tuesday if he doesn't make the tour, and is then told by Wallabies' coach Eddie Jones that he does not figure in his 2007 World Cup plans any more, he will head overseas.
Whitaker has been understudy to Australia skipper George Gregan in 76 Tests but, with his Australian Rugby Union contract due to expire at the end of the year, is now looking at his options.
"If I'm not in their plans, I'll look overseas, probably the UK," he said.
"I don't want to hang around too long, that's for sure.
"Also, from the team's point of view, I don't want to be standing in the way of someone who is in their plans, to give Australia the best opportunity to win the World Cup."
But Whitaker confirmed his immediate goal is to make the 45-man Wallabies' train-on squad for the European Spring Tour, which will be named on Wednesday.
"I still believe I have plenty to offer the Wallabies," said the experienced number nine, who has made 91 Super 12 appearances for the Waratahs.
"I'm not sure what will happen (for the rest of the year) but I still want to be part of the World Cup campaign."
Whitaker said the Wallabies' winter had not been all doom and gloom, despite the disappointment of losing their last five Tests and finishing bottom of the Tri-Nations table.
"We played some attractive rugby in patches," he said.
"There was also the opportunity to bring in new players, such as Drew Mitchell, which would not have happened without the injuries to key players such as regular full-backs Mat Rogers and Chris Latham.
"We have a good structure in place and I'm sure we can turn it around."
Whitaker said he had also taken the opportunity to talk with captain and good friend Gregan before the loss to the All Blacks in Auckland.
"I had a good chat with him," Whitaker said. "He's doing fine and remains strong.
"He has copped a lot of the flak because of the team not playing well but he is still a great influential leader.
"I have accepted my role as understudy (to Gregan) and I am looking forward to the tour."
Whitaker expects the tour, which includes internationals against France, England, Wales and Ireland, will provide a stern test.
"France in Marseille are always difficult, as are England in Twickenham," he said.
"But it will also be interesting to see the new-look Wales and Ireland at Lansdowne Road.
"Previous tours may have had peaks and troughs but these four games will all be tough."