Cowboys’ defensive tackle Willie Blade sprained his left knee in Sunday afternoon's practice and will miss four to six weeks.
Blade had been working well for the first time in his NFL career until the injury. He had worked his way into the first-team nose tackle position along side La'Roi Glover.
"That's a setback for us because he was doing very well," head coach Bill Parcells said.
Blade had distinguished himself from John Nix, Shaun Smith and Michael Myers, who signed a one-year deal to remain with Dallas.
Blade was injured on the initial play of team drills in the afternoon. He hobbled off the field and did not return to practice despite trying to walk the injury off.
Further tests revealed a sprained medial collateral ligament.
Parcells said it was unlikely the team would look for a replacement in the free agency market.
"I have three guys that can play the position, but one of them needs to step up and show me they can play it."
Blade will probably miss only two games - the season opener hosting Atlanta and at the New York Giants. The Cowboys have a bye in week 3 so Blade could return in week 4 when the Cowboys travel to New York to play the Jets.