The San Francisco 49ers have been dealt a devastating blow this week as star defensive end Nick Bosa will miss the entire 2025 season due to a torn ACL. During Sunday’s nail-biting 16-15 victory against the Arizona Cardinals, Bosa left the game in the first quarter after suffering a significant knee injury.

Head coach Kyle Shanahan confirmed the heartbreaking news during a Monday afternoon conference call, revealing that Bosa’s MRI results showed a complete ACL tear. This injury is particularly gut-wrenching for the 49ers, as it mirrors Bosa’s previous ACL injury from Week 2 of the 2020 NFL season, this time affecting his right knee instead of his left.

During the game, Bosa’s injury concerns became apparent when he visited the medical tent and emerged giving a thumbs-down gesture, signaling the potential severity of his condition. Initially, the team held out hope that the injury might not be as serious as it ultimately proved to be.

For a team with strong championship aspirations, losing a defensive powerhouse like Bosa is a massive setback. Known for his exceptional pass-rushing skills, Bosa has been a critical component of the 49ers’ defensive strategy. His absence will require significant adjustments from the team’s coaching staff and defensive lineup.

The 49ers now face the challenging task of adapting their defensive scheme without their star player, a scenario eerily similar to their experience five years ago when Bosa previously suffered a season-ending injury. The team will need to dig deep and rely on their depth and resilience to maintain their competitive edge in what promises to be a challenging season.

As the NFL season progresses, all eyes will be on how the 49ers manage this significant loss and whether they can overcome this substantial blow to their roster.