The 34-year-old left-handed batsman, recalled to the Australian team this week at the expense of Simon Katich, is scheduled to appear in a Melbourne court on Monday to give an eye-witness account of the late-night altercation that led to the death of Hookes, one of his close friends.
The rest of the Australian squad will be in Brisbane preparing for next Thursday's first of two Tests against the Kiwis and the earliest Lehmann can rejoin them is on Tuesday.
Bouncer Zdravko Micevic, 22, is facing a charge of manslaughter over an alleged fatal attack on Hookes outside a Melbourne hotel on January 18 this year. The committal hearing is set down for 10 days.
Lehmann, respected as having one of the best cricketing brains in the country, said he is not looking forward to the court experience and that it will make for a difficult preparation for the Kiwi Test.
"It isn't a nice thing and will be a difficult preparation," Lehmann wrote in his Adelaide newspaper column on Thursday.
"It's something I'm not looking forward to but it has to be done. It is a responsibility I have to fulfil.
"Undoubtedly, Hookesy will be in my mind when I go out to bat in Brisbane."
Australian team Coach John Buchanan admitted on Friday the court hearing was bad timing but did not believe his team's preparations would be compromised.
"He'll be up Monday afternoon or evening so that's not a major concern," he said.
"We've got our two main sessions on the Tuesday and Wednesday and he'll be available for those."
But Buchanan felt Lehmann would feel better for the court experience, allowing him to put the initial phase of the prosecution behind him.
"It obviously was an important moment in his life, considering his association with David and so it will probably be very good for him to have all that cleared behind him before the summer season starts," Buchanan said.
Lehmann's manager Rick Olarenshaw said Friday Lehmann was hopeful he would not miss anything more than Australia's first full day in training camp.
"He's hoping he'll be straight in and out and he wouldn't have to be there on the Tuesday as well," Olarenshaw said.
Buchanan said he did not expect Lehmann, who tore his hamstring in the third Test against India in Nagpur, would need a fitness test when he arrived in Brisbane.
"All the medical reports are good on him and he's been working solidly," he said.