Ngata will help to replace defensive tackle Beau Allen, who is not expected to re-sign with the Eagles.
Ngata, 34, spent the past three seasons with the Lions, who acquired him in the wake of Ndamukong Suh signing with the Miami Dolphins. Ngata played 32 games for Detroit, making 53 tackles with six sacks.
He also was a large part of Detroit’s run defense the past three years and served as a mentor to younger defensive linemen in the room, including A’Shawn Robinson and Akeem Spence. He suffered a biceps injury against the Carolina Panthers in Week 5 of the 2017 season, which resulted in him going on injured reserve.
In January, Ngata told 97.1 FM in Detroit that he wanted to continue to play in 2018. Before the 2017 season, Ngata went to the The Sports Neurology Clinic at the CORE Institute in Brighton, Michigan, to have his brain checked before deciding to play.
“I don’t want to have problems when I’m older. I want to be able to raise my kids and be able to play with them when they are older and still be able to beat them in wrestling matches and stuff when they are teenagers,” Ngata said in 2017.
The No. 12 overall pick by the Ravens in the 2006 draft, Ngata spent nine years with Baltimore, being named AP first-team All-Pro twice and making five Pro Bowls. He also won Super Bowl XLVII with the Ravens.
Ngata has played in 167 games, making 499 tackles with 31.5 sacks, 6 forced fumbles, 5 fumble recoveries and 5 interceptions. He also has 27 career pass breakups.
ESPN’s Michael Rothstein contributed to this report.