Hewitt, 29, is playing in the Kooyong Classic for the first time in his professional career in a revamped preparation for the Open, which he was runner-up at in 2005 and has reached the round of 16 twice since.
Austria's Jurgen Melzer, ranked 11th, and Russian Nikolay Davydenko, 22nd, were named Monday in the final two berths for the January 12-15 Kooyong tournament.
Czech Tomas Berdych, Russia's Mikhail Youzhny, Spaniard Fernando Verdasco and French players Jo-Wilfried Tsonga and Gael Monfils are already confirmed for the eight-man showpiece.
A string of injuries have seen former world number one Hewitt slip to 54 in the rankings but he said he and coach Tony Roche had decided to try a long lay-off followed by the Hopman Cup-Kooyong double hoping for a "fresh start".
"I still feel when I play my best tennis ... I'm able to compete against the best guys," Hewitt said.
"It's all about scheduling and what I believe to be the best preparation to win a Grand Slam for me," he added. "It's also about trying something different."
Hewitt said the January 1-8 Hopman Cup in Perth and Melbourne's Kooyong Classic would guarantee him "at least three matches in both events, if not four."
"That gives me great preparation, I feel, for the Australian Open," he said.
Hewitt said the injury setbacks had made him think about retiring "a little bit more because you never know what's absolutely around the corner," but said he did not plan on giving up tennis anytime soon.
"This won't be my last, but I don't have a number," said the former US Open and Wimbledon champion of his Australian Open ambitions.
Added Hewitt of his hopes for 2011: "If I play a full year I'd like to finish in the Masters Cup."
"If I do what I think I'm capable of in the bigger tournaments and especially the Grand Slams then I think it's a realistic goal."