Allen Park — Kelvin Sheppard knows what people have thought about the Detroit Lions in years past.

The Lions, under a head coach who came up under Sean Payton, have predominantly relied on their offense to win games in recent seasons. It’s easy to see why. Dan Campbell spent a decade in the NFL playing on that side of the ball, and the Lions roster some the league’s best offensive talent. Why not lean into it?

But in his first season as defensive coordinator, Sheppard set out for his half of the ball to pull more weight. He desired a complementary situation, with the defense helping out the offense as much as the offense had been helping out the defense.

Sheppard’s efforts have largely been successful through 10 games. The defense having the offense’s back is best illustrated in sudden-change situations, when the opponent takes over possession after an interception, fumble, turnover on downs, missed field goal or blocked punt.

The Lions have faced 20 of these moments this season. They’ve given up only two touchdowns, and that’s despite the opponent’s average drive starting within five yards of midfield. There were six sudden-change instances in last week’s loss to the Philadelphia Eagles. The Lions held the Eagles out of the end zone each time, limiting the damage to three made field goals.

“It started back in the offseason, and it started at training camp. We went into this thing understanding that we wanted to play complementary football,” Sheppard said this week. “We didn’t want to just live on the back of our offense. … That narrative has been such in Detroit, that we win games because of offense. As a defensive player, as a defensive coach, that’s a luxury. But at the same time, it makes you feel a certain type of way.”

The Lions have allowed an average of 21.6 points and 291.8 yards per game this season, numbers that rank 10th and fifth in the NFL, respectively. They’re also near the top of the league in run defense (99.7 yards, eighth), pass defense (192.1, eighth) and, notably, third-down defense (34.4%, fourth).

Getting off the field in those critical moments goes a long way when there’s sudden change.

“We’re the firefighters on this team,” Sheppard said. “What does that mean? If Jack Fox, which he rarely does, shanks a punt, we’re not complaining, nobody’s sucking their teeth. We’re running on the field even faster to make sure we’re able to go put out that fire. That’s the mentality you’ve got to have as a defensive player. No pointing the fingers. No ‘what if’ this, no ‘what if’ that.”

With the defense playing as well as it’s been, and with the offense — outside of an exception versus the Washington Commanders — sputtering since Week 7, some have suggested it’s time for Campbell to have a philosophy change. Campbell’s aggression on fourth down is well documented. It’s worked well in the past because the Lions needed their offense to win them games. Maybe that’s no longer the case, and maybe Campbell should prioritize putting the defense in positions to succeed.

Ask Sheppard, though? He sees Campbell’s gambling mentality as a nod to his group: “I love it. I absolutely love it. Because that speaks volumes to me directly that our head coach believes, no matter where I put this defense, they’re going to put the fire out. So, I don’t care if Dan goes for it on every fourth down. It’s our job as defense to go out there and stand tall in that test.”

“We want this to be a complementary team. … We want to win because we win in all three phases of the game, and I think that’s something this team is trending towards. … You see it, when the offense is on, when the defense is on, when the special teams is on, man, we have a chance to do something special this year,” Sheppard said.

rsilva@detroitnews.com

@rich_silva18