The Cowboys plan to use Roy Williams in Week 7 against the Rams

Coordinator Jason Garrett's system is digital like the one Williams played in for Detroit, but it will probably take him another week to get starter's snaps. Considering the matchup, though, he's not an awful WR3 bet. It will be interesting to see if Dallas puts Williams at Z receiver. He was an X in Detroit, but that's Terrell Owens' position and T.O. probably won't move.
Source: Dallas Morning News