Cooper (heel) missed his fifth consecutive day of practice Thursday, Calvin Watkins of The Dallas Morning News reports.
He was able to do some rehab work on the side, however. The issue isn't expected to linger into the regular season, but the Cowboys don't want to risk the health of their No. 1 wide receiver -- and given that Cooper's in the final year of his rookie contract, the feeling is certainly mutual. It would be a shock if the 25-year-old suited up for the team's preseason opener Saturday against the 49ers.