The team's leading rusher in the preseason, Williams was among seven signed to the practice squad Sunday, a day after the roster had to be cut to 53 players.
Williams spent three injury-filled seasons with Arizona after the Cardinals drafted him early in the second round in 2011.
The Cowboys claimed guard Donald Hawkins from Cleveland and waived tackle John Wetzel.
Dallas added three veterans to its practice squad in receiver Tim Benford, safety Micah Pellerin and defensive end Kenneth Boatright. The Cowboys brought back three waived rookies in center Ronald Patrick and linebackers Keith Smith and Will Smith.
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