The 37-year-old revealed on a Dutch talk show that he was diagnosed with the incurable disease a month ago.
Ricksen struggled to speak in an interview on Nederland 3's The World Keeps Turning. He said: "I find it difficult to talk because I've got ALS [Motor neurone disease]."
His biographer Vincent de Vries stepped in and explained: "Fernando has been diagnosed with a muscle disease, ALS. He's going to hospital tomorrow to discuss the diagnosis in detail with the hospital and the doctors."