Who is Orin Incandenza from Infinite Jest: A Novel and what is their importance?

Orin Incandenza is the son of Avril and James Incandenza and the brother of Hal and Mario Incandenza. He is a football player with the Arizona Cardinals. He is also estranged from everyone in his family, except for his brother, Hal. He used to date a woman named Joelle Van Dyne, but after breaking up with her, he becomes a serial womanizer. Orin did attend the Enfield Tennis Academy, but when it became clear he was not a extraordinary player, he switched to football in college and found his true sports niche.