Kaka, captain Riccardo Montolivo and fellow midfielder Andrea Poli are all set to miss the visit of the Scottish champions and Milan head coach Massimiliano Allegri claims his list of absentees is like a "wartime news bulletin".
Forwards Stephan El Shaarawy and Giampaolo Pazzini are also out of the Group H Opener, along with defenders Ignazio Abate, Mattia De Sciglio, Matias Silvestre and Daniele Bonera.
But Celtic have their own injury problems as midfielder Joe Ledley is a major doubt with a groin injury and winger James Forrest and midfielder Beram Kayal have been ruled out.
"It is very unfortunate for him that these injuries have come all at the one time and it is not an ideal situation," said Lennon.
"But I am sure as the season and the campaign progresses Milan as always will get better and stronger.
"I can't look too much into Milan's problem I have to concentrate in my own.
"The fact that he can maybe bring (Alessandro) Matri in to the team, he cost a lot of money, money that myself or my board of directors can only dream of paying for players.
"I can't really offer up a lot of sympathy at this stage for him."
Lennon insists he is a big admirer of the hosts' temperamental striker Mario Balotelli, who will definitely start against Celtic.
"Balotelli is a wonderful footballer," he said.
"Having seen him live for the first time on Saturday (against Torino), he is very powerful, very skilful. He takes the ball in under pressure from people and likes to get them turned.
"When he is in full flow he is very quick and strong, can hold defenders off, he is a good finisher.
"People question his temperament but I would have him in my team if I had the opportunity.
"He was very popular in England at Manchester City, he is young, he has so much ahead of him in his career."
You can watch AC Milan v Celtic live on Sky Sports 2HD at 7.30pm