The two sides had until 4 p.m. to sign a deal. Because they didn't, Ansah will play this season under the $17.143-million franchise tender he signed in April.
Next year, the Lions will have to make a contract decision again with Ansah. They can either let him explore the market as an unrestricted free agent, sign him to a multiyear extension or use the franchise tag again, but at a much steeper $20,571,600 salary for 2019, when he will be 30.
The Lions have wanted to take a wait-and-see approach to Ansah this season with the new defense that will be used under rookie coach Matt Patricia, who has called Ansah "an outstanding player."
In February, Patricia and general manager Bob Quinn met with Ansah and laid out their plans.
"We're not going to get into talking about it with you guys," Quinn told reporters. "But we did talk to him, told him what our plan was and he understands where we're coming from. We understand where he's coming from and we're looking forward to having him on the team."
Part of the concern with Ansah is his injury history. Although he hasn't missed many games, injuries have limited his effectiveness. Last season, Ansah had 12 sacks, but he struggled to make an impact for large stretches as he fought through knee and back injuries.
Ansah has 44 sacks in five seasons. In 2015, he posted a career-best 14.5 sacks and made the Pro Bowl. This offseason, Ansah had a clean-out procedure on his knee and has practiced little.