The Hoops made an error when they allowed Ambrose to start in the Champions League Round of 16 against Juventus at the beginning of the year, just a day after flying back from Nigeria's successful African Cup of Nations campaign.
On that day in February, Ambrose put in a poor performance as Celtic lost 3-0 at home suggesting to Lennon that he should be given some time off after representing his country at the Confederations Cup in Brazil this month.
"Aye, we'll learn from that one," he told the Sunday Mail.
"He won't be back until the 15th, so he'll miss a huge chunk of pre-season.
"Efe's a fine athlete but he needs rest."