The veteran Swedish midfielder struggled for game time at Parkhead after arriving in January and has spoken out about his time at the club, saying that he could not work out why he never received minutes when Lennon kept telling him he was doing well on the training ground.
"It's better that it happened when I was 34 rather than 20," explained Ljungberg to Aftonbladet.
"You want to be professional and you've got to keep on training without complaining.
"I asked why I didn't get to play. I expected him to say something about me not being good enough and that I hadn't shown anything at training or something like that.
"But instead he thought that I was fantastic. That I was outstanding at training and that he wanted to keep me on for many years. I was completely blown away. I had expected a totally different answer.
"He thought that I should be happy (playing the big games) at my age, but I thought the opposite. I wanted to play every game, otherwise I wouldn't have gone there.
"Even my team-mates, players I was competing for a spot with, came up to me and asked me if I had been in a fight with Neil, and maybe that was the reason I wasn't playing.
"I got to know the nicest nationality of people that I ever met. The Scots are fantastic, but I never got the chance to show what I can do, and that's frustrating."