Yes, Jamal Adams is out for the entire 2026 season. He suffered a non-contact right knee injury during preseason Week 1 against the Giants on August 15 — just 12 snaps into his Vikings debut. Head coach Kevin O'Connell said initial imaging "didn't look good," and it was later confirmed as a season-ending knee injury (from the Jamal Adams page).
Given his extensive history of major injuries (torn quad, shoulder surgeries, and prior knee issues dating back to his Seahawks days), the report also notes there's legitimate concern about whether his NFL career continues after this setback.