Myles Garrett will undergo arthroscopic knee surgery and miss at least four games on injured reserve, multiple outlets reported Sunday, Sept. 13.

The Rams' prized offseason acquisition has not been right since early in training camp. Garrett managed the knee with rest and rehab for weeks, practiced sparingly, then played despite the injury in the Sept. 10 season-opening 27-7 loss to the San Francisco 49ers in Melbourne, Australia. He played 40 of 65 snaps and generated a team-high five quarterback pressures, according to NFL.com. He recorded zero sacks and zero tackles. It was only the fourth time in his career he failed to record a tackle.

"This was the worst version of myself that I've put out there," Garrett told reporters after the Melbourne loss on Sept. 10, according to the Los Angeles Times.

The Ringer's Tom Pelissero first reported the surgery. Fox Sports NFL insider Jay Glazer confirmed it on "FOX NFL Kickoff," and ESPN's Adam Schefter and NFL Network's Ian Rapoport also confirmed the move. The Athletic reported a team source confirmed the decision.

Garrett is eligible to return Oct. 18 against the Arizona Cardinals in Week 6. The four games he will miss include Monday Night Football against the New York Giants on Sept. 21, plus matchups with the Denver Broncos, Philadelphia Eagles and Buffalo Bills. All four opponents reached the 2025 playoffs.

The timing compounds an already painful start. Los Angeles traded Pro Bowl edge rusher Jared Verse, a 2027 first-round pick, a 2028 second-round pick and a 2029 third-round pick to the Cleveland Browns for Garrett. He is a two-time NFL Defensive Player of the Year who set the league's single-season sack record with 23 sacks in 2025.

Acquiring Garrett also helped convince three-time Defensive Player of the Year Aaron Donald to come out of retirement, according to The Athletic. Donald did not travel to Melbourne to complete his ramp-up after two seasons away. That means the Rams' dream defensive pairing will not share a field until at least Week 6.

Without Garrett, Byron Young and Josaiah Stewart will handle the edge roles, with Kobie Turner and Braden Fiske rotating in on run downs, The Athletic reported. Young was limited during training camp with a knee injury of his own, according to the Los Angeles Times. In the Melbourne loss, the entire Rams defense managed zero sacks and just two quarterback hits against 49ers quarterback Brock Purdy.

The Rams entered 2026 as the favorite to win Super Bowl LXI, scheduled for SoFi Stadium in February 2027. Their next game is Monday, Sept. 21, when they host the Giants at SoFi Stadium.