Jesse Minter’s days as the Chargers’ defensive coordinator were numbered.

He knew it. His fellow coaches knew it, too.

So did the front office.

So did the players.

Even the beat reporters assumed Minter would be hired elsewhere as a head coach, after two highly successful seasons guiding one of the best defenses in the NFL. Only the date and the destinations were mysteries when the season ended with an AFC wild-card loss Jan. 11 to the New England Patriots.

It was a no-brainer.

So, when Minter departed Jan. 22 to become the Baltimore Ravens’ head coach, Chargers general manager Joe Hortiz did his due diligence before selecting Chris O’Leary as the next defensive coordinator, a move that made sense on so many levels, including his intriguing résumé.

O’Leary was a Minter disciple from his earliest collegiate days as a scout team quarterback and later a wide receiver at Indiana State, where Minter was an assistant coach. They would team again as coaches at Georgia State, Florida Tech and then with the Chargers during the 2024 season.

Six days after Minter’s departure, Hortiz hired O’Leary, who spent this past season as the defensive coordinator at Western Michigan University, and gave him his matching orders. O’Leary’s task is to make a stingy defense for the past two seasons even stingier.

O’Leary sounded up for the challenge.

“Number one, we’re going to elevate what we do well,” he said Feb. 3. “The foundation of our defense, we’re going to elevate that. We’re going to do what we do and do it better. The second thing we’re going to do is we’re going to evolve the defense. We’re going to add things. We’re going to tailor things to the players, the personnel that we have going into the season. We’re really focused on taking what we built and the foundation that’s laid and taking it to another level.”

ALSO READ: Chargers offseason primer: Offense and Justin Herbert need help

What follows in the coming weeks and months will give a hint about O’Leary’s plans for the 2026 season and beyond. Minter established a standard that could be difficult to match. After all, the Chargers had the NFL’s top defense in the 2024 season and were ninth-best in ’25.

Free agency begins March 11. The NFL draft is April 23-25.

Here’s an offseason primer focused on the Chargers’ defense:

Returning starters: DL Jamaree Caldwell, LB Troy Dye, CB Cam Hart, LB Daiyan Henley, CB Donte Jackson, S Derwin James Jr., S Elijah Molden, CB Tarheeb Still, DL Teair Tart, OLB Tuli Tuipulotu.

The Chargers’ secondary appears set with James, a five-time Pro Bowl pick, joined by Molden at the safety positions and Hart, Jackson and Still as possible starters at cornerback. But defensive backs are like relief pitchers in baseball. You can never have enough good ones on the roster.

O’Leary was thrilled to resume his working relationship with James, in particular.

“He’s the ultimate competitor,” O’Leary said. “Spending the year I did with him here (in the 2024 season) … one of my favorite players I’ve ever worked with and coached because of how contagious his energy is and how great he wants to be. I can’t put it into words. I’m ready to get started right now.”

Caldwell emerged as a quality lineman in his rookie season, but there remain questions about the Chargers’ defensive front as Hortiz and head coach Jim Harbaugh continue their quest to establish supremacy in the trenches with a physical style of play that makes the team tough to play against.

Henley was the Chargers’ leading tackler this past season with 101 total, including 52 solo. He had 3.5 sacks, six quarterback hits and two interceptions while taking another confident step as a team leader in his third season after he was drafted in the third round in 2023.

There’s a great deal to like about a Chargers defense that gave an average of 20 points per game, ninth best in the NFL in ‘25, one season after limiting opponents to a league-best 17.7 points in ‘24. Adding depth, talent and experience during the offseason will continue its excellence.

Upcoming unrestricted free agents: DL Da’Shawn Hand, S Tony Jefferson, DB Deane Leonard, OLB Khalil Mack, DL Otito Ogbonnia, OLB Odafe Oweh, LB Denzel Perryman, LB Del’Shawn Phillips, CB Benjamin St-Juste.

Upcoming restricted free agent: S Kendall Williamson.

Hortiz has a number of ways to go with his own free agents, but keeping his core group together, especially his outside linebackers, sounded like a top priority when he held his season-ending news conference last month. Actually, he said he would like to retain as many as possible.

Read below for additional details.

2026 salary cap: $83.5 million cap space, based on a projected $295 million cap, per the indispensable website overthecap.com.

2026 cap commitments: $224.5 million.

2026 cap commitments (defense only): $82.9 million.

Toughest decisions: Mack nearly became a free agent last year, waiting until almost the last minute before signing a one-year extension with the Chargers for his fourth season with the team and his 12th overall in the NFL. He had considered retirement, but only briefly.

Whether he decides to continue his Hall of Fame-caliber career with the Chargers or another team or decides to call it quits will have a big impact on O’Leary and Hortiz’s plans for the future. Oweh also is a pending free agent, a player who showed his value after a trade from the Ravens.

Plus, Tuipulotu is eligible for a contract extension.

So there are big decisions to be made at the outside linebacker position.

“We’re going to fight to keep as many players as we can,” Hortiz said.

Hortiz made one move already, signing Tart to a three-year extension worth up to $37.5 million, retaining the services of one of the Chargers’ top run defenders one season after they couldn’t come to an agreement with standout lineman Poona Ford, who signed with the Rams.

“I don’t want to spend recklessly,” Hortiz said. “You do have to be calculated. You have to be smart. We’re going to spend money, but we’re going to spend internally because there are a lot of guys we’d like to have back. So, that large amount of cap space, just like last year, we had a lot of cap space and Rashawn ate up a lot of it.”

Hortiz referred to the four-year, $114 million extension Pro Bowl offensive lineman Rashawn Slater signed July 27, which with an average annual salary of $28.5 million made him the highest-paid offensive tackle in the NFL. The contract topped the $27.5 million the San Francisco 49ers paid Trent Williams.

It could be well-spent money assuming Slater returns to form after a season-ending knee injury last August in training camp. Unlike the Chargers’ offense this past season, their defense mostly managed to avoid the sort of long-term injuries that left it shorthanded at key positions.