The former Alabama standout was trying to come back from two seasons wrecked by knee injuries when he ran into his latest health setback.
"Although disappointing, I am a fighter and will handle this," Williams said in a statement released by the Seahawks. "I am going to focus on my health and fighting this battle with a return to football as my ultimate goal. Thank you for your thoughts and support. Go, Hawks!"
In the same statement, John Schneider, Seattle's executive vice president and general manager, said: "Jesse is an extraordinarily tough individual who has overcome a great deal in his life and we will support him in any way possible. He is in our thoughts and prayers."
According to the Kidney Cancer Association, surgery is considered the primary treatment for kidney cancers. Papillary renal cell carcinoma is often slow-growing and non-metastatic. However, type 2 of the disease can be more aggressive.
Seattle drafted Williams in the fifth round of the 2013 NFL Draft after he played on Alabama's 2011 and 2012 BCS national championship teams, but he has not played in a Seahawks game.
To continue reading this story on al.com, click here