Dallas placed Cooper on the PUP list at the start of training camp after he underwent ankle surgery in January.
His return doesn't mean he will practice immediately. According to the Dallas Morning News' Michael Gehlken, Cooper is likely to participate in "mock games," which are effectively walkthroughs, before he ramps things up and is a full-go in practice.
Cooper has a month to prepare for the Cowboys' season opener against the Super Bowl champion Tampa Bay Buccaneers.
The 27-year-old finished last season with 92 receptions (on 130 targets) for 1,114 yards and five touchdowns.