He becomes a free agent in March, and after an injury-plagued year that limited his production, the Lions might not be willing to re-sign him.
Ansah, the fifth overall pick in the 2013 NFL Draft, made $17.1 million this season by playing on the franchise tender for defensive ends.
He played in just seven games, including two starts, this season because of multiple shoulder injuries, and he recorded only four sacks and 12 total tackles.
That will hurt his negotiating power when he becomes a free agent.
Ansah is in his sixth NFL season and has 48 career sacks. That includes the 12 sacks he had last season and the 14.5 sacks he had in 2015 when he was named to the Pro Bowl.
The Lions also put tight end Michael Roberts on injured reserve because of a shoulder injury.
Roberts had nine catches for 100 yards and three touchdowns this season.
He was a fourth-round pick of the Lions in the 2017 NFL Draft, and he had four catches for 46 yards last season as a rookie.