The experienced all-rounder was cleared this week of a serious left hamstring injury he picked up during Australia's recent tour of India, raising concerns that he could miss the Test opener at Brisbane starting on November 21.
But Lehmann said Watson was making good progress and was in line to play at the Gabba.
"The reports from our medical team on Shane's recovery from injury are pleasing," Lehmann said in a Cricket Australia statement.
Lehmann said Watson would miss New South Wales' Sheffield Shield game with Queensland this week.
More From This Section
"We won't be taking any chances with his preparation. We want him to continue his treatment, and if all goes to plan, join the Australian team in camp ahead of first Test in Brisbane," Lehmann said.
Team physiotherapist Alex Kountouris said this week he was quietly confident Watson would be ready, describing the injury as "a low-grade muscle strain".
"He will have intense treatment and rehabilitation and just how well he responds to this will determine how quickly he can resume full training and match preparation," he said.