Killerbowl by Gary K. Wolf
Self-published Kindle edition, 2017
Originally published by Doubleday, 1975
Price I paid: $2.99
Thirty years in the future, the ultraviolent sport of Professional Street Football, a phenomenally popular 24-four-hour-long athletic event, combines pro football with mixed martial arts and armed combat. On New Years day, quarterback T.K. Mann plays the most dangerous game of his life, the game known as Killerbowl!
(Synopsis from Goodreads)