EL SEGUNDO — When they began to survey the roster and all that went haywire before their arrival, general manager Joe Hortiz, coach Jim Harbaugh and defensive coordinator Jesse Minter decided the Chargers’ defense could be and should be upgraded for the 2024 season.

Small changes were made, minor tweaks that got little notice around the known football universe. Mostly, though, there was a buy-in from the players that Hortiz, Harbaugh and Minter noticed from the first days of practice in the spring. Matters could be improved by leaps and bounds without major changes.

Joey Bosa and Khalil Mack, two veteran outside linebackers and cornerstones of the defense, agreed in the offseason to take pay cuts so Hortiz could make the moves he made and still remain under the salary cap. According to Minter, it “set an unbelievable tone” for what was to follow.

Poona Ford strengthened the defensive line. Denzel Perryman did the same with the inside linebackers. Bud Dupree added depth to the already fearsome outside linebacker corps. Defensive back Elijah Molden was the latest addition, acquired after training camp, and he was an impact player.

In no time at all, it became evident that the Chargers had created something special. By midseason, they were firmly entrenched as the NFL’s stingiest defense, with a chance to give up the fewest points in the league in a season for the first time since they were the AFL champions way back in 1963.

Going into their regular-season finale against the Raiders (4-12) on Sunday in Las Vegas, the Chargers (10-6) have given up 17.6 points per game, the fewest in the NFL. They’re coming off a playoff-clinching victory over the New England Patriots in which they gave up only a touchdown and an extra point.

“What we found, and I don’t know if (Harbaugh) has said this, but there was an unbelievable thing going on here,” Minter said. “For whatever reason. It wasn’t like you had to change a bunch of guys’ attitudes and work ethic. It was unbelievable from the second we walked in the door, and I think it’s gone both ways.”

Now, finishing the regular season with the NFL’s best defense is a pride thing.

“It’s cool, man,” Mack said. “It’s a cool goal, something we probably didn’t think we could accomplish early in the season. To have that opportunity, that capability, is dope. Carrying that into the postseason (next week) and getting better is the ultimate process for us right now.”

Mack and safety Derwin James Jr. were named Thursday to the Pro Bowl for the ninth time and fourth time, respectively, in their careers. They were honored, but it wasn’t as if they were the only standouts in a defense that has set a high standard for success in the new regime’s first season.

“It would mean a lot because that was our ultimate goal,” James said of the possibility of having the league’s top defense after Sunday’s game against the Raiders. “Every day we break it down to be the best. That’s our mindset. That’s our goal. We take the field to do that every day.

“It’s coming out strong, starting fast. You’ve got to start the game fast, and I feel like we’ve been starting out fast on defense all year long. We’ve also finished games good, too. So, we just want to continue to build on that. Every guy is working toward that. We’re definitely getting better as a team.”

INJURY REPORT

The Chargers ruled out running back Gus Edwards (ankle) and wide receiver Joshua Palmer (foot) for Sunday’s game, but their status for the wild-card playoff game next weekend was uncertain. Linebacker Denzel Perryman (groin) was doubtful to play Sunday and safety Alohi Gilman (hamstring) was questionable. Gilman has been sidelined since he was hurt in a game Nov. 25 against the Baltimore Ravens.