The former NFL rushing champion assumed a reserve role with the Ravens this past season, gaining 444 yards and scoring two touchdowns while backing up Ray Rice. The news of Williams calling it a career comes two weeks after he said that he intended to return to the Ravens for the final season of his two-year contract.
The 34-year-old veteran spent his first three NFL seasons with the New Orleans Saints, who traded all six of their choices in the 1999 draft, and two picks the following year, to move up and select the former Texas standout with the fifth overall pick in 1999.
Williams twice reached the 1,000-yard plateau with the Saints, then led the NFL with 1,853 rushing yards in his first season with Miami in 2002. He added 1,372 yards the following year, then abruptly retired just before training camp in 2004.
The 1998 Heisman Trophy winner rejoined the Dolphins in 2005, only after the team had demanded that he return bonus money for breach of contract. He then was suspended for the 2006 season after his fourth violation of the league's drug policy.
Unable to play in the NFL in 2006, Williams inked a one-year deal with the Toronto Argonauts of the Canadian Football League. With the Argos, he rushed for 623 yards on 124 carries and caught 24 passes for 193 yards. He also missed two months of the season due to a broken arm.
Williams played just one game in 2007 before rebounding to rush for 1,121 yards and 11 touchdowns two years later. He was no longer the feature back in his final season with the Dolphins, totaling only 673 yards in 2010.
For his career, Williams has run for 10,009 yards with 66 touchdowns in 147 NFL games.