Ricky Williams is retiring again. The 34-year-old running back has informed the Ravens that he will not fulfill the second year of his contract with the club.

As a back-up to Ray Rice this past season the 34-year-old Williams ran for 444 yards and two scores.

Williams retired previously once before the 2004 season when facing a four-game suspension for violating the league’s drug policy. He returned in 2005, then left to spend the 2006 season with Toronto of the Canadian Football League.

Since winning the Heisman Trophy at Texas and joining the New Orleans Saints in 1999, Williams has rushed for 10,009 yards and scored 74 touchdowns. He is one of only 26 NFL running backs to rush for more than 10,000 yards in a career.

“The NFL has been an amazing page in this chapter of my life,” Williams said in a statement released by the University of Texas. “I pray that all successive adventures offer me the same potential for growth, success and most importantly fun. I want to thank all my fans, teammates, coaches and supporters for the strength they've given me to overcome so much. I want to especially thank my family, Coach Mack Brown, Coach [Mike] Ditka, Coach [Bill] Parcells, Ronnie Brown, Wilbert Montgomery and the Jamail family for believing me. As for what's next, I am excited about all the opportunities ahead. Continuing my education, running The Ricky Williams Foundation and whatever other opportunities present themselves.”

Williams led the NFL in 2002 with 1,853 yards rushing for the Miami Dolphins and received his lone Pro Bowl invitation that season. He backed that up with 1,372 yards in 2003, giving him what remains the two most productive rushing seasons in Dolphins history.