Cowboys defensive end Randy Gregory suffered a "substance-related relapse" in August, according to ESPN's Adam Schefter, and may face discipline from the NFL.
Gregory will suit up for Dallas' Week 1 matchup with Carolina on Sunday but could be disciplined by the league as early as next week.
A second-round pick out of Nebraska in 2015, Gregory has missed 30 of the Cowboys' last 32 regular season games. He was suspended for the entire 2017 season in January 2017 after violating the NFL's substance abuse policy. Gregory was reinstated by commissioner Roger Goodell in July.