Linebacker Asmar Bilal and defensive tackle Justin Jones also landed on IR, with guard Ryan Groy, linebacker Malik Jefferson and defensive end Jessie Lemonier being activated.
Ingram had dealt with knee soreness, an issue that had gotten worse during the week, according to head coach Anthony Lynn, resulting in the lineman's being held out of Friday's practice. Ultimately, the team chose caution and placed the 31-year-old pass-rusher on IR.
He'll be eligible to return in three weeks.
Ingram's career once seemed like it would be defined by injuries. He played 13 games in 2013 and 2014 combined because of a torn ACL but started every game over the next four seasons and 13 last year.
Ingram started slow this season with no sacks or quarterback hits through two games, though he has two pass breakups.
The Chargers still have Joey Bosa on the other side of the defensive line to keep opposing quarterbacks honest. With Ingram out, the team will likely turn to Uchenna Nwosu.