The Chargers’ blockbuster trade for star edge rusher Khalil Mack was likely the start of a drastic makeover for Brandon Staley’s defense.

Staley’s history of helping young defensive players reach their potential played a part the Chargers’ decision to hire him as the head coach last year, but Staley has often shifted the praise toward the players for making him better. He knows his two-high defensive scheme, which has had plenty of success in today’s pass-heavy NFL, doesn’t work without the talented players.

That’s what the Chargers are after – talent and lots of it. Mack, a six-time Pro Bowler, certainly fits the description as one of the game’s elite pass rushers.

Last season, the Chargers struggled to generate a pass rush outside of edge rusher Joey Bosa. They lacked game-changing defensive plays other than the handful of impact plays safety Derwin James made.

The Chargers probably assumed Staley, who calls the defensive plays, could make it work with Bosa, James and a young supporting cast, but that led to poor results, especially against the run and on third down.

Chargers general manager Tom Telesco heavily invested on the defense by drafting defensive tackle Jerry Tillery and linebacker Kenneth Murray in the first rounds in 2019 and 2020, respectively. He spent a second-round draft pick on edge rusher Uchenna Nwosu in 2018 and on safety Nasir Adderley in 2019.

These players have struggled to find consistency and have shown flashes, but they were drafted for a different coaching staff and scheme. Perhaps they’ll eventually play to their draft billing, but they might not be the right fit for Staley.

Telesco sounded disappointed and surprised about the defensive struggles during his end-of-season news conference. Staley tried it with the defensive roster that Telesco constructed before he got there, but the Chargers were 30th in the NFL in points allowed. Now Telesco and Staley have shifted to a different approach, evident by the trade with the Chicago Bears for Mack.

Telesco and Staley likely have had lengthy discussions on which defensive players are right for the Chargers. Nwosu, a pending free agent, was probably one of those players, but it’s hard saying no to Mack, especially when it only took a 2022 second-round pick and a 2023 sixth-round pick to land the three-time first-team All-Pro.

Nwosu could be headed elsewhere when the legal tampering period begins Monday morning to kick off free agency.

“Business is business,” Nwosu tweeted this weekend.

Defensive tackle and pending free agent Justin Jones has a strong chance of returning because the Chargers’ run defense was productive when he was on the field, but injuries have been an issue for the 2018 third-round draft pick.

Another intriguing in-house free agent is linebacker Kyzir White, who had a breakout season in 2021 by quickly grasping Staley’s defensive scheme. The Chargers might need to ask themselves whether it’s time to move on from Murray if they want to retain White.

Murray lost his starting role to White early in the season and appeared lost in the new scheme, but there might not be a strong trade market for Murray and that could buy him a third season to prove himself.

The Chargers were busy the week before free agency by trading for Mack and re-signing wide receiver Mike Williams to three-year, $60 million contract extension. Those moves took a chunk of the Chargers’ cap space, but they still have $21.81 million to work with, according to OvertheCap.com.

That could be enough for the Chargers to go after a top cornerback and an interior defensive lineman in free agency. Or for a right tackle and special teams help. The Chargers could create an extra $10.75 million in cap space if they decide to release right tackle Bryan Bulaga, who has only played in 11 games since joining the team in 2020.

The Chargers have many position needs, but they’ve already shown that they’re willing to swing big to improve the roster. Here’s a look at potential outside free agents the Chargers could target when frenzy begins.

DEFENSE

CORNERBACK

J.C. Jackson, 26, Patriots

Many NFL insiders have reported that the Chargers have a strong interest in Jackson, who has had a combined 17 interceptions the past two seasons.

OTHERS TO TARGET: Carlton Davis, 25, Buccaneers; Stephon Gilmore, 31, Panthers; Darious Williams, 27, Rams; Bryce Callahan, 30, Broncos

DEFENSIVE TACKLES

D.J. Jones, 27, 49ers

Staley heavily praised the 49ers’ defensive line when they arrived in Costa Mesa last summer for a scrimmage against his team. He probably took notice of the talented run stopper.

OTHERS TO TARGET: Bilal Nichols, 25, Bears; Foley Fatukasi, 27, Jets; Sebastian Joseph-Day, 26, Rams

SAFETY

Tyrann Mathieu, 29, Chiefs

Mathieu and James spent plenty of time together at the Pro Bowl. Mathieu showed last season he still has plenty left in the tank.

LINEBACKERS

Bobby Wagner, 31, free agent

It’s hard to believe the Seahawks parted ways with Wagner after he was named to another All-Pro team last season.

OTHERS TO TARGET: De’Vondre Campbell, 28, Packers

OFFENSE

OFFENSIVE LINE

James Daniels, 24, OG, Bears

Daniels has plenty of upside and could fit in nicely at right guard if the Chargers don’t re-sign Oday Aboushi, who played well until he tore his ACL in Week 5 of last season.

OTHERS TO TARGET: Joe Noteboom, 26, OT, Rams; Trent Brown, 28, OT, Patriots; Laken Tomlinson, 30, OG, 49ers; Morgan Moses, 31, OT, Jets; Austin Corbett, 26, OG, Rams; Riley Reiff, 33, OT, Bengals; Andrew Norwell, 30, OG, Jaguars

WIDE RECEIVERS

Cordarrelle Patterson, 30, RB/WR/KR, Falcons

Patterson makes plenty of sense because he would help in many areas, and he’s familiar with Staley and special teams coordinator Ryan Ficken.

OTHERS TO TARGET: Russell Gage, 26, Falcons; D.J. Chark, 25, Jaguars

RUNNING BACK

Rashaad Penny, 26, Seahawks

The Chargers need a bruising running back to complement Austin Ekeler. Penny, a Norwalk High grad, had a prolific final month of the season with the Seahawks.

TIGHT ENDS

O.J. Howard, 27, Buccaneers

The former first-round pick has plenty of upside and would help Herbert in the passing game.

OTHERS TO TARGET: Zach Ertz, 31, Cardinals

SPECIALIST

Bryan Anger, 33, P, Cowboys

The Chargers have prioritized special teams lately and they are in need of a punter with Ty Long struggling the past two seasons. Anger, a Camarillo native, had another impressive season.

CHARGERS IN-HOUSE FREE AGENTS

Chris Harris Jr., CB; Linval Joseph, DT; Jared Cook, TE; Oday Aboushi, OG; Kyler Fackrell, Edge; Ryan Smith, CB; Uchenna Nwosu, Edge; Andre Roberts, WR/KR; Michael Schofield, OG; Senio Kelemete, OG; Chase Daniel, QB; Matt Overton, LS; Dustin Hopkins, K; Christian Covington, IDL; Davontae Harris, CB; Trey Marshall, S (RFA); Stephen Anderson, TE; Justin Jones, DT; Ty Long, P (RFA); Kyzir White, LB; Storm Norton, OT (ERFA); Scott Quessenberry, C; Justin Jackson, RB.