Baltimore Ravens running back Ricky Williams will announce his retirement from pro football for a second time, according to ESPN NFL Insider Adam Schefter.

Williams previously retired from football on August 2, 2004 after violating the NFL's substance-abuse policy for a third time. Williams re-joined the Miami Dolphins on July 24, 2005 before violating the policy for a fourth time, which resulted in him being suspended for the entire 2006 season. 

The 34-year-old played 11 NFL seasons for the New Orleans Saints, Miami Dolphins and Baltimore Ravens. 

The former Heisman Trophy winner rushed for 10,009 yards and 66 touchdowns in his troubled NFL career.