Chung was charged with felony cocaine possession earlier this month after a June incident at his home. While he was not arrested at the time, an investigation gave police probable cause to charge Chung with a crime.
The Patriots have said they are not commenting on the case while it is an active legal matter. Chung remains a member of the team's active roster.
Michael McCann of Sports Illustrated noted that it is "not surprising" that Chung entered a not guilty plea because the cocaine was found in a home owned by him, not on his person. It's possible Chung will contend the cocaine was not his and was someone else's in the home or a guest's.
Chung has spent nine of his 10 NFL seasons with the Patriots, winning three Super Bowls. He has played in 78 of a possible 80 regular-season games over the last five seasons since returning to New England after a one-year stint with the Philadelphia Eagles.
The 32-year-old posted 84 tackles and one interception in 2018, his fifth straight season with over 80 tackles.