Ziggy Ansah, the Detroit Lions' only legitimate pass-rushing threat, won't be on the field when training camp opens Sunday.
The Lions placed Ansah and guard Brandon Thomas on the physically-unable-to-perform list Saturday, and added offensive tackle Greg Robinson and defensive end Cornelius Washington to the non-football injury list.
Ansah missed three games and was severely limited by a high ankle sprain last season, when he finished with a career-low two sacks.
The Lions held Ansah out of some drills during spring workouts. Their decision to start him on the PUP list is believed to be precautionary.
Currently, the Lions have just five healthy defensive ends. Ansah and Washington join Armonty Bryant and Jeremiah Valoaga on the PUP list. Bryant also will serve a four-game suspension to start the regular season.
The Lions also removed cornerback Teez Tabor and offensive tackle Cyrus Kouandjio from the non-football injury list Saturday, making both available for Sunday's first practice.
Kouandjio, who signed with the Lions in June after undergoing off-season hip surgery, could take first-team reps at left tackle with Taylor Decker (shoulder) and Robinson hurt.
Decker is expected to miss about the first half of the season with a torn labrum in his right shoulder.