The Detroit Lions' defense has reached historically poor levels through the first four games of the 2026 season, allowing a league-high 1,695 yards and 127 points. Following a 32-26 loss to the Carolina Panthers, head coach Dan Campbell refused to discuss the job security of defensive coordinator Kelvin Sheppard, insisting the team will improve through internal adjustments rather than staff changes. While the defense has surrendered at least 30 points in three of four games, Campbell warned against panic, noting the team is still 2-2 with 13 games remaining. The Lions' secondary struggled significantly against Carolina's offense, particularly allowing second-year wide receiver Tetairoa McMillan to record 14 receptions for 192 yards and two touchdowns. Despite the defensive collapse, quarterback Jared Goff threw for 412 yards, but the offense failed to convert drives into touchdowns, settling for four field goals before a late score. The team is now facing scrutiny over its defensive scheme and player positioning, with Campbell promising to exhaust all strategic options before considering further changes.