Largely a backup for his entire career, Jason Garrett enjoyed his career highlight in Dallas on Thanksgiving Day 1994. Garrett led the Cowboys to a come-from-behind victory over the Packers, finishing with 311 passing yards and two touchdowns. When he was named the interim head coach of the Cowboys on Nov. 8, 2010, Garrett piloted a similarly shocking upset: a 33-20 victory over the favored New York Giants at the Meadowlands. In January 2011, he was officially named head coach of the Cowboys. What other current NFL head coaches spent their younger days on the gridiron? SI.com takes a look.