Onyemata, who has recorded 6.5 sacks in the last two seasons, previously was issued a misdemeanor summons for marijuana possession in February, according to ESPN.
The 26-year-old defensive lineman has developed into a key role player among the Saints' defensive line, averaging 510.7 snaps per season. New Orleans selected Onyemata in the fourth round of the 2016 NFL Draft.
Onyemata registered 4.5 sacks and a forced fumble last season and played about 60 percent of the Saints' defensive snaps as a key reserve at both tackle positions.
The Saints signed former New England Patriots defensive lineman Malcom Brown and Mario Edwards Jr. in free agency to add depth to their defensive front.
New Orleans plays the Houston Texans in its season opener Sept. 9.