With stand-in ODI skipper George Bailey out form with the bat in the Tri-Series, it's cast an unwelcome air of doubt around the World Cup campaign. But Lehmann says it should end.
"I don't know why we're worried about leaders too much," Lehmann said in Brisbane on Wednesday. "At the end of the day, we know he (Clarke) is going to be right to go.
"We're really confident in that, and he's confident - that's more important. We need him playing and playing well ... and leading well.
"He's ahead of schedule ... he plays tomorrow, he gets through that no dramas, another box ticked and away we go."
Clarke has been given until Australia's second World Cup pool match against Bangladesh to prove his fitness or be ruled out of the World Cup. But Lehmann appeared to hint on Wednesday he could even make a surprise return in the opening match against England at the MCG on February 14.
"When he gets back we've got to make sure he's right to go. We can't afford it to keep going on us in important stages," Lehmann told Adelaide radio station FIVEaa. "He knows that, he's diligent, he's good to go and really confident he'll be right to lead us hopefully before Bangladesh, but definitely by Bangladesh."
Lehmann shrugged off any suggestions of a rift between Clarke, his teammates, the selectors and Cricket Australia administrators.
"You've just got to deal with it, don't you?" he said. "Everyone's entitled to their opinion but, for us, we know where we're at as a squad. We're in a good space."
Clarke made the first step in his comeback on Saturday in Sydney grade cricket, batting for almost three hours on his way to a score of 51. Assuming he is declared fit, his spot in the team will not necessarily come at the expense of vice-captain Bailey, Lehmann said.
Bailey has made just 21 runs from his past four ODI innings and it has been anticipated Clarke will come in as a direct swap.
"George is George. He needs to make some runs like everyone else in the side, there's no doubt about that. He knows that better than most," Lehmann said. "There's no difference between the top player and the 15th player. We're a squad and one thing I do know of World Cups, you need a squad to win it.
"I can't complain about his work ethic and everything he's brought as a captain to the table. It's just a bit of confidence, and that can happen in this game as we know.
"As selectors, we'll sit down and work out what the best side is and what the best combo is when they're all fit and available."
-AAP