The NFL reinstated Gregory on a conditional basis on Tuesday, allowing him to be at camp and participate in meetings, conditioning work and similar activities, but he has not been cleared to practice or play in games.
He will be fully cleared to return after arrangements regarding his clinical resources in Dallas are confirmed and if he continues to abide by the league's substance abuse policy.
"I wasn't surprised because I think we all felt pretty confident that I'd get back in," Gregory told ESPN when asked about his reaction to the news. "We were assuming it would be around Friday so when I got the news I was shocked and happy. Not surprised. It's a good moment. I can't say it's the same feeling as draft night or even getting my first sack, but definitely a big accomplishment for me. I think a lot of people thought I wouldn't be able to do this.
"My story is so much more than just what it looks like on the surface where people thinking I'm a weed smoker and sitting around, just a pothead. That's probably a fifth of what we've done the last two, three years. To say I've come back from all of that and on the right track mentally and physically, it's a blessing."
Gregory has missed 30 of the past 32 regular-season games for multiple violations of the league's substance abuse policy.
Gregory went through rehabilitation, held a job and put his life in order during his time away from the Cowboys. He met with NFL commissioner Roger Goodell last month in New York as part of the reinstatement process, and his legal team, led by attorney Daniel Moskowitz, supplied the league a vast array of test results, recommendations and personal letters from teammates Sean Lee, Tyrone Crawford and Jeff Heath.
"It was a yearlong effort of ups and downs, but at the end of the day Randy has earned this," Moskowitz said. "He has done more than anybody who has been involved in this process."
The Cowboys are scheduled to fly to Oxnard next Tuesday and hold their first training camp practice on July 26.
"I don't have any crazy expectations," Gregory told the Dallas Morning News. "Try to be the best professional I can on and off the field. I think I've shown that off the field these last months and now I'll prove it on the field. I feel like I'm definitely capable of doing that."
The Cowboys have held on to Gregory's rights despite his off-field troubles but have operated under a worst-case scenario that he would not play in 2018. Throughout the offseason, owner and general manager Jerry Jones, executive vice president Stephen Jones, coach Jason Garrett and defensive coordinator Rod Marinelli expressed hope that Gregory could return.
"I have been proud of Randy during this offseason," Jerry Jones said on May 9. "I'm very aware of how hard he's working to get back in the league and get back on the field."
Gregory fell to the Cowboys in the second round of the 2015 draft because of off-field issues during his time at Nebraska. Jerry Jones was willing to take a chance on Gregory and hoped that a support system that had helped other players through the years would help Gregory.
Gregory played in 12 games as a rookie in 2015, missing four with an ankle injury. He ended up in the NFL's substance abuse program in 2016 and was initially suspended the first four games of that season. Another failed test led to an additional 10 games, but he was able to return for the final two regular-season games and recorded the first -- and so far only -- sack of his career.
He was suspended for a year before the 2016 playoffs and has not been around the team since.
Gregory said if he had been asked a year ago if he would be back in the NFL, he would have said no and he understands this is his final chance.
"It is and if it's not I'm definitely treating it like it is," Gregory told ESPN. "I feel like a lot of other organizations wouldn't have stuck around for this long. I think part of it is just the faith in what I can do on the field, but they also saw that I was a struggling kid that was trying to get himself back on the right path. I always tried. It wasn't that I didn't try.
"I just lost a lot of confidence. I'm a totally different person than I was coming into the league. In some ways better. I think Jerry and the whole organization, they understood the situation fully and there was going to be some setbacks. Hopefully this is the last one as far as all that."
The Cowboys retain Gregory's rights through 2020 because of the suspensions. He signed a four-year deal in 2015.
The Cowboys like the depth they have built on their defensive line with DeMarcus Lawrence (who had 14.5 sacks in a Pro Bowl season in 2017), David Irving, Tyrone Crawford, Taco Charlton and others. Gregory, who has been working out since his meeting with Goodell to get ready for football, showed flashes of ability when on the field but was hardly close to a finished product.
"It's kind of like golf, if you don't play for three or four [months] a year, it's not the same, the timing," Marinelli said earlier in the offseason. "I'm just excited to hopefully get a chance to work with him again."