Terms of the deal were not disclosed by the Lions, but multiple media outlets reported that Ayers agreed to a one-year contract.
Cornerback Josh Okonye was waived to open a roster spot for Ayers, who recorded 31 tackles, two sacks and two forced fumbles in 12 games last season with the Tampa Bay Buccaneers.
Ayers has collected 264 tackles, 35 sacks and nine forced fumbles in 120 career games with the Denver Broncos, New York Giants and Buccaneers. He was selected with the 18th overall pick of the 2009 NFL Draft by the Broncos.
The 32-year-old Ayers joins a Lions’ defensive end cast that is headlined by Ezekiel Ansah.
Ansah, who is playing under a $17.143 million franchise tag, is working his way back following offseason knee surgery. The fifth overall pick of the 2013 NFL Draft, Ansah recorded a team-high 12 sacks, 44 total tackles, one forced fumble and one fumble recovery last season despite missing two games with a back injury.
Kerry Hyder, Anthony Zettel, Alex Barrett, Da’Shawn Hand, Cam Johnson and Jeremiah Valoaga are also defensive ends on the roster.
The Lions’ pass rush has struggled this offseason, as the club did not record a sack in its first two preseason games before finally grabbing the quarterback against the Buccaneers.