Williams joins the recently signed Jerious Norwood behind starter Steven Jackson. Adding Norwood seemed a little odd because the team still did not have a No. 2 power back. Williams fills that role. He is a hard runner and could give the Rams another physical presence in the backfield. Norwood adds more of a speed dimension when healthy.
Those last two words -- when healthy -- come up frequently in relation to Norwood and Williams. Norwood missed all but two games last season. Williams has not missed a game over the last two seasons. He missed 22 over the 2007 and 2008 seasons.
Williams started nine games for Tampa Bay last season, but the Bucs often limited his role to passing situations. Coach Raheem Morris lauded Williams for accepting his role in the best interests of the team. There will be no doubt about the hierarchy in St. Louis, where the depth chart at running back has long read, "Steven Jackson and then everyone else."
Williams, 29, suffered severe knee injuries during the 2007 and 2008 seasons. He has not averaged better than 3.9 yards per carry in a season since 2005, his rookie year.
The Rams have been seeking depth at running back, but it's unclear how much of the workload they'll lift from Jackson's shoulders. Jackson has 907 carries over the past three seasons, trailing only Adrian Peterson (960) and Chris Johnson (925). He has 1,490 carries since 2006, most in the league.