Barry Sanders poses with his bust after his induction into the Pro Football Hall of Fame, Sunday, Aug. 8, 2004, in Canton, Ohio. (AP Photo/Ron Schwane)

NFL prospect C.J. Spiller (right) and Hall of Fame running back Barry Sanders greet fans upon arriving for the 2010 NFL Draft at Radio City Music Hall in New York City, NY on Apr. 22, 2010. (AP Photo/Ben Liebenberg)

Detroit Lions running back Barry Sanders poses for a portrait in 1998 in Detroit, Michigan. (AP Photo/Tom DiPace)

Lions former player Barry Sanders with Commissioner Roger Goodell during the 2011 NFL Draft at Radio City Music Hall on April 29, 2011 in New York, NY. (AP Photo/Ben Liebenberg)

Detroit Lions running back Barry Sanders (20) poses for a photo with a lei on photo day during the week of the 1990 NFL Pro Bowl between the National Football Conference and the American Football Conference on Jan. 30, 1990 in Honolulu. The NFC won the game 27-21. (AP Photo/Paul Spinelli)

NFC Hall of Fame running back Barry Sanders (20) of the Detroit Lions carries the football during the NFC's 21 - 15 victory over the AFC in the 1992 NFL Pro Bowl played on February 2, 1992 at Aloha Stadium in Honolulu, Hawaii. (AP Photo / Al Messerschmidt)

Oklahoma State's running back Barry Sanders poses with his Heisman Trophy at New York's Marriott Marquis Hotel Thursday, December 8, 1988. Sanders, who was awarded the prize while in Japan for the Coca-Cola Bowl last week, holds the trophy during a news conference. (AP Photo/Susan Ragan)

Circa 1990's: Barry Sanders of the Detroit Lions. (Sportswire via AP Images)

IMAGE DISTRIBUTED FOR EA SPORTS - NFL hall of fame running back Barry Sanders holds up a mock up of the Madden 25 video game cover during the EA Sports Madden NFL 25 Cover Reveal on SportsNation on Wednesday, April, 24, 2013 in New York, New York. (Photo by Chris Park/Invision for EA Sports/AP Images)

Detroit Lions running back Barry Sanders carries the ball during an NFL football game against the Green Bay Packers at Lambeau Field on November 21, 1993 in Green Bay, Wisconsin. The Packers won 26-17. (AP Photo/David Stluka)

FILE--Former Detroit Lions running back Billy Sims, left, gives rookie Barry Sanders a hug after Sanders broke Simms' rookie rushing record of 1,303 yards in 1989 at the Pontiac Silverdome in Pontiac, Mich. Sanders is quitting football, despite the near certainty of becoming the NFL's career rushing leader this season. "My desire to exit the game is greater than my desire to remain in it. I have searched my heart through and through and feel comfortable with this decision," Sanders said in a statement released Wednesday, July 28, 1999. (AP Photo/Duane Burleson, file)

FILE--Detroit Lions first round draft pick Barry Sanders appears during a news conference after signing his first NFL contract at the Pontiac Silverdome in Pontiac, Mich., in 1989. Sanders is quitting football, despite the near certainty of becoming the NFL's career rushing leader this season. "My desire to exit the game is greater than my desire to remain in it. I have searched my heart through and through and feel comfortable with this decision," Sanders said in a statement released Wednesday, July 28, 1999. (AP Photo/John Stormzand, File)

FILE--Detroit Lions first round draft pick Barry Sanders, right, holds his jersey with Lions vice president of finance Chuck Schmidt at the Pontiac Silverdome in Pontiac, Mich., in 1989. Sanders is quitting football, despite the near certainty of becoming the NFL's career rushing leader this season. "My desire to exit the game is greater than my desire to remain in it. I have searched my heart through and through and feel comfortable with this decision," Sanders said in a statement released Wednesday, July 28, 1999. (AP Photo/John Stormzand, File)

Detroit Lions running back Barry Sanders is carried around the field by teammates after he rushed for 184 yards and the winning touchdown in a 13-10 comeback victory against the New York Jets at the Silverdome in Pontiac, Mich., Dec. 21, 1997. (AP Photo)

Detroit Lions running back Barry Sanders (20) sets to take the field in 1997 at the Pontiac Silverdome in Pontiac, Michigan. (AP Photo / Al Messerschmidt)

NFL FILE: Barry Sanders of the Detroit Lions. (Sportswire via AP Images)