The 27-year-old Luxembourger struggled in the Adelaide heat and abruptly returned to his hotel after a mechanical problem in Sunday's final stage ended his Tour Down Under campaign prematurely.
Still fighting to recover from a broken pelvis suffered during the Criterium du Dauphine last June, Schleck, however, remains confident he will be in prime shape for the 100th edition of the Tour de France starting in Corsica on June 29.
"I have no doubt I have the engine to come back," said Schleck, who was almost 40 minutes behind the leader when he abandoned on Sunday.
"It's just a matter of working well and doing the right things. I need to be patient."
The crash prior to last season's Tour de France ruined his 2012 season and an overweight Schleck staged a brief, unimpressive comeback at the Tour of Beijing in October.
"My feelings are a lot better - if you have pictures from Beijing, I was basically a fat pig then," he said.
"I was 4kg more than now."
Looking ahead to the Tour de France, Schleck highlighted the firepower of the British Team Sky outfit comprising defending champion Bradley Wiggins, Chris Froome and Schleck's former Saxo Bank team mate Richie Porte.
"I see him as a really big guy this year," the 2010 Tour de France winner said of Australia's Porte.
"Last year he improved a lot. I knew him when he was with us and he can go really well. I believe he can climb as well as Froome and Bradley.
"Maybe he's the guy they don't announce."