The pass-rusher will need commissioner Roger Goodell to lift his latest suspension in order to return to the field. The league now has 60 days to make a decision on Gregory's status.
If his petition is successful, Gregory is expected to have another opportunity with the Cowboys, reports David Moore of the Dallas Morning News. Dallas reportedly extended his contract through 2020 last April.
The NFL suspended Gregory indefinitely in February 2019 for violating its substance abuse policy and the terms of a previous conditional reinstatement. The 27-year-old was reportedly expected to apply for reinstatement heading into training camp eight months ago. A slip-up during his aftercare program and a change in his representation delayed those plans, though, sources told Moore.
Gregory has been suspended four times since entering the league in 2015. He was first suspended for four games in 2016 after failing a drug test and was banished for another 10 games later that season. He received a yearlong ban in 2017. The NFL will no longer suspend players for positive marijuana tests, a stipulation of the league's new collective bargaining agreement.
Gregory has played in just 28 regular-season games since 2015 while missing 52 contests - 46 due to suspensions - but he's flashed talent when on the field. The former second-round pick amassed six sacks, two forced fumbles, and 15 quarterback hits through 14 games in 2018.