Hodgkin's lymphoma is a cancer that starts in the the tissues and organs that produce, store, and carry white blood cells, which fight infections, according to the Centers for Disease Control and Prevention.
Symptoms include swollen lymph nodes, fever, night sweats, feeling tired and weight loss. It's unclear whether Moreau noticed any of those symptoms prior to the diagnosis.
Hodgkin's lymphoma is considered one of the most curable forms of cancer, according to the Leukemia and Lymphoma Society. Treatment options include chemotherapy and radiation.
Moreau has not said what type of treatment he plans to undergo.
The 25-year-old thanked his supporters for standing by his side during this time. The Raiders tweeted Moreau saying, "Your Raider family is with you, Foster."
