The Detroit Lions have some tough decisions on the horizon if things don't change defensively.

Through four games, the Lions' defense ranks near the bottom of the league in a number of different categories. Coordinator Kelvin Sheppard has struggled to manage the game, and his defense has been caught out of position several times leading to explosive plays.

In particular, the secondary has really struggled as shown in front of a national audience on Sunday against the Carolina Panthers. This performance sparked a debate on whether the defense's difficult fortunes are the result of coaching or personnel.

Ultimately, Sheppard will enter the team's Week 5 game on the hot seat given the team's start to the season. This naturally leads to speculation about who could be next if the Lions were to part ways with him.

While the most likely path forward would be an in-staff promotion on an interim basis, the impending offseason hiring cycle is beginning to take shape based on the start of the season. In particular, there are several defensive-minded head coaches currently on the hot seat who could be candidates to land coordinator jobs if they aren't able to salvage their respective seasons.

Here are three head coaches who are viewed as being on the hot seat that could be potential candidates to replace Kelvin Sheppard in the event that the Lions elect to move on from him at defensive coordinator.

Todd Bowles

After a promising start to his tenure in Tampa Bay, things have gone south in a hurry for Bowles. He took over for Bruce Arians in 2022 and inherited a roster that featured Tom Brady, but a rough start to the 2026 campaign has things trending downward.

Bowles has made three playoff appearances as the leader of the Buccaneers, but has won 10 games in just one season since taking over. His team started the 2025 season 6-2, but is 2-11 in the 13 games since then including an 0-4 start to the season this year.

With Baker Mayfield sidelined due to injury, the Buccaneers were unable to salvage a win at home against Green Bay on Sunday. Bowles has had some success as a defensive coordinator, however, most notably winning a Super Bowl with the Buccaneers prior to being promoted.

If the Buccaneers can't get back into what is considered a weak NFC South division race, they may have no choice but to move on from the defensive-minded leader.

If he were to be available, he has some history working with Campbell dating back to their time together with the Miami Dolphins and could be an intriguing veteran option to add to the coaching staff.

Dan Quinn

Like Bowles, Quinn has seen some of the good will generated early in his tenure erased by a tough start. However, his situation is somewhat different than Bowles as he's just two years removed from an upstart run to the NFC title game in the first year of his partnership with quarterback Jayden Daniels in Washington.

Quinn is in his second stint as a head coach, as he previously reached a Super Bowl during a six-year stint as the leader of the Atlanta Falcons. However, he was fired after an 0-5 start that followed two straight losing seasons after that Super Bowl run.

After leaving Atlanta, Quinn put together three years of top-10 defenses as the coordinator for the Dallas Cowboys, and found his way to Washington for a second chance at being a head coach.

Quinn's success has been somewhat derailed by injuries, which makes it tough to project his future. Daniels has dealt with elbow injuries early this year and most of last, which has left the head coach shorthanded at arguably the most important position.

If Washington continues to struggle and Quinn becomes available, he's a no doubt candidate to help stabilize Detroit's defense.

Aaron Glenn

Glenn may have the hottest seat of any coach in the NFL at this stage, as the Jets have had some struggles in big situations with regards to game management leading to a 1-3 start. This comes after a 3-14 record a season ago, and leaves him facing plenty of criticism.

This begs the question of whether or not Campbell would be open to a reunion with the coordinator he spent the first four seasons of his tenure in Detroit with. There's no doubt that Campbell and Glenn have plenty of camaraderie, based on their interactions ahead of and after the Lions and Jets met in Week 3.

Often times in the NFL, coaches don't return to places they've been in the past to take the same role. However, if Glenn can't cut it in the eyes of the Jets as a head coach, perhaps Campbell would be willing to facilitate a reunion if Sheppard is unable to right the ship.