The 37-year-old Haddin retired last week after keeping wickets in 66 tests, scoring 3,266 runs at an average of 32.98 and taking 262 catches.
"We can't afford to lose those blokes to the game," Lehmann told Adelaide radio station 5AA.
"We need him to pass on the knowledge to the next generation which will stand them in good stead.
"He'll do some work coaching-wise with New South Wales, and we're going to get him involved with the (Under) 19s and (Under) 17s Australian programs, and I might even be able to take him away with (the Australian men's team) occasionally.
"It's a great stage for him to move forward with the next stage of his life and career.
"We think he's a really important part of what we started and we love how he goes about it and what he does."
Haddin follows former captain Michael Clarke, all-rounder Shane Watson and opening batsman Chris Rogers into retirement after the 3-2 Ashes defeat in England. Paceman Ryan Harris also quit before the Ashes after suffering a serious knee injury.
New captain Steve Smith will lead Australia's most inexperienced test side in decades into next month's two-match tour of Bangladesh.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ