Celtic issued a statement expressing sadness about Ricksen's condition and Lennon added a personal touch yesterday by saying how stunned he was. Ricksen and Lennon clashed in several Old Firm games and each was an iconic figure for his club. But all tribal rivalries were rendered irrelevant by the news.
"It's devastating for him and it's devastating for the community here," said the Celtic manager. "He was a big player; a character and a personality. You think people like that just go on and on so when news like this comes out of the blue it puts a different perspective on things.
"It possibly resonates more with Celtic fans because it's the same disease 'Jinky' [Jimmy Johnstone] had. But more so it's just because he was a player who was very high profile here, a huge personality and the fact he is so young. He is only 37 and for him to have to deal with something like that now seems so unfair.
"Everyone here at Celtic is with him. The fact we did lose 'Jinky' to it and saw him suffer with it, we hope that Fernando finds strength with his friends and family. It's a bit like Stiliyan [Petrov]'s situation. He was playing for Aston Villa on the Saturday and the following Friday he's diagnosed with leukaemia. It's just really hard to comprehend that but there by the grace of God go us all. It's horrendous. It's one of those things that just knocks you for six. I only found out about it on Thursday morning and saw footage of Fernando on the TV. I know there are different strains of it. I think there's five, four of which are terminal and one that you can maybe recover from, so hopefully it's that one."
Lennon reflected on Ricksen's playing days with affection and respect. "There were times when he wasn't right in the head, but I'm sure Fernando would admit that himself. I'm sure the boys at Rangers would tell you plenty stories about him as well. He was nuts at times but there's no malice to him.
"He was a very good athlete, technically a good player too and the longer that he was here the better he played. I think he found it hard, like most people do, to adjust to the pressure cooker in Glasgow. When you're young you think it's magic and you love the limelight but after a couple of years he matured into a really good player.
"He was versatile, I think he played in midfield for one season and he and John Hartson ended up getting jointly awarded Player of the Year that season [2004-05]. That showed the calibre of player that he was. Dick Advocaat was a big fan of his and Dick knows a player or two. He had a very good career here."