Perryman was helped off the field during Sunday's game against the Oakland Raiders and was not able to return. Per Rapoport, he suffered an injury to his LCL and he also likely will need surgery on his hamstring.
He is expected to return to the field in three to four months.
The Chargers are one of the hottest teams in the NFL with six straight wins to get to 7-2 on the season. However, the latest injury could be a significant setback for the entire team.
Perryman has 51 tackles in nine games, which trailed only rookie safety Derwin James for the most on the team. He has also played well in coverage with an interception and two passes defended.
Los Angeles currently ranks eighth in the NFL in points allowed, but losing the starting linebacker could be damaging for a defense that is already playing without star pass-rusher Joey Bosa. Starters Jason Verrett and Kyzir White are also already on injured reserve.
Jatavis Brown will have to play a bigger role at linebacker with Perryman unavailable, while Uchenna Nwosu and Kyle Emanuel should each see more snaps going forward.
Meanwhile, the injury is a major disappointment for Perryman himself as durability remains a problem for the 25-year-old. He has failed to play a full season in any of his first four years in the NFL, while his 2017 season was limited to just seven games due to hamstring problems.
With a relatively short rehabilitation period, he will hope to find more luck during the 2019 season.