Surgeons discovered the hip problem the right-back has been struggling with this season was far worse than first feared during a routine operation.
And the Swede, one of the Scottish champions' star performers during the 2013/14 campaign, will now be sidelined for up to four months.
But Lennon has no fears about Efe Ambrose suffering the same fate as Lustig in the months ahead as his side pursue another league and cup double.
For the Nigerian defender never gets tired, never gets injured, never wants a rest and never misses a game.
"It is by the grace of God they find someone like me," he laughed, with his tongue placed firmly in his cheek, at Lennoxtown yesterday.
"We are few! They are lucky to have somebody like me! I have always been like this. I keep playing 365 days a year.
"I never get injured or tired, I just want to keep playing. I never get tired. I just sleep. The next day I am ready to go."
The Celtic manager has been delighted with the partnership Ambrose has formed with Virgil van Dijk in the heart of his rearguard this season.
But he is concerned about the number of matches, both domestic and European, he has asked them to play and is keen to give them both a rest.
The injury problems he has at the moment - Charlie Mulgrew will once again be unavailable for the SPFL Premiership match with Hearts at Parkhead today - mean he is unable to do so.
Ambrose, who has played in 27 games for his club this term as well as making international appearances for his country, is not bothered in the slightest.
He said: "For me, football is what I love. I enjoy playing every time. When I wake up in the morning I just want to play. I just feel like playing every day.
"If the manager wants to give me a rest that is his own opinion. But for me, I will never say no to football. I just want to play football every day."
That will be music to his manager's ears as he looks to try and maintain his side's unbeaten run in the Premiership and retain the William Hill Scottish Cup.
Ambrose refused to speculate on the possibility of the Hoops going through the top flight this season without losing a game.
But he has vowed to give his all in every match his side take part in between now and the end of the campaign as they pursue their objective.
He said: "The league has so far to go. We will just keep looking ahead of us and the next game is Hearts. We will see what goes on.
"But the most important thing is to just keep winning the games that come by. You never know where that will take us by the end of the season."
Ambrose has enjoyed playing alongside Lustig in defence and is hopeful the right-back makes a swift recovery from his operation.
But he is optimistic that whoever replaces him, whether it is Adam Matthews or Darnell Fisher, will help ensure Celtic extend their unbeaten run.
He said: "Mikael is the one person who had really solidified the defence.
"Playing with him has pulled me along. He has helped me a lot, communicated with me, told me how to play, to do this and that. I have enjoyed playing with him.
"Adam, too, is good. Darnell has come in and is improving. But I believe we are going to miss Mikael, his height, his pace and everything in the defence.
"But, as you know, we are a team. Anyone who comes in to fill his shoes will do the same. But at the same time we want to wish him a quick recovery and we hope to see him soon."
Ambrose continued: "Adam Matthews is a good player. You can't compare them, they have different quality in the game.
"Adam is coming in, but he, too, has been injured. He is just coming back. We also have Darnell.
"We will see what the manager wants to do. As I say, we are a team and we will stay as a team and help each other out on the pitch."
Ambrose was pleased to see Teemu Pukki end his 15-game scoring drought in the 1-0 win over Hibs at Celtic Park last weekend.
He believes the Finnish striker, a close-season signing from Bundesliga club Schalke, has the potential to be a regular scorer for the Glasgow club.
He said: "I think he's going to improve.
"He's been looking for a goal and I believe scoring against Hibs will bring him back to his scoring ways and it will help him to do that.
"As a striker when you don't score you get frustrated. But he kept training hard and tried to do what he could do best for the team and at last it has paid off against Hibs.
"When he gets there I think he's going to be a good player. He's very calm, a cool guy."
Ambrose and his Celtic team-mates were helpless to prevent Barcelona running riot and scoring six goals in their final Champions League group match in the Nou Camp earlier this month.
But the African star, who will be playing for Nigeria in the World Cup, reckons they have got that painful reverse out of their systems.
He said: "It was a difficult night for us against Barcelona, but for us that game is in the past.
"And keeping a clean sheet against Hibs shows we have overcome what happened and we're moving forward.
"It's not been easy, but that can happen as Barcelona are the best team in the world and nobody can dispute that when they are in their best shape, their best form, they can score five or six against any team because they have the quality to do that.
"But the most important thing is that we learn from the game and how we improve ourselves as a team and individually.
"The game has helped us a lot and how we focus. We're working towards that."