(Frisco, TX) — Six starters were held out of the Cowboys’ practice. Pro Bowl wideout Amari Cooper sat out with a thigh contusion and ankle issue. Slot receiver Randall Cobb missed the session with a back injury. Starting offensive tackles Tyron Smith and La’el Collins did not practice because of ankle and knee injuries. Cornerbacks Anthony Brown and Byron Jones were held out with hamstring issues. The Cowboys signed defensive lineman Justin Hamilton to replace Tyrone Crawford, who is scheduled for hip surgery.