LOS ANGELES -- Sharing a stadium with the defending Super Bowl champions in a market that has been home for five seasons would have a profound effect on any NFL team. If the Los Angeles Chargers aren't coming out and saying that directly with words, they undoubtedly are with their actions.

By the time the NFL's early negotiating window opened, the Chargers had already re-signed receiver Mike Williams to a deal paying him about $20 million annually and traded for edge rusher Khalil Mack. They were just getting warmed up.

On Monday, the Chargers landed the best cornerback on the market in J.C. Jackson, formerly of the New England Patriots. ESPN's Adam Schefter reported the Chargers and Jackson agreed to a five-year, $82.5 million deal with $40 million guaranteed. That $16.5 million average would be tied for the sixth highest among NFL cornerbacks, tying Byron Jones' deal with the Miami Dolphins from 2020.

As though adding Jackson and Mack wasn’t enough, the Chargers are signing a couple of run stuffers to sizable contracts to bolster a unit that gave up the third most rushing yards in the NFL last year. Defensive tackles Austin Johnson (two years, up to $14 million) and Sebastian Joseph-Day (three years, up to $24 million) also agreed to new deals with the Chargers, according to multiple reports.

These are the types of deals a team makes either because it is in rebuilding mode and has plenty of cap space or because it believes it has a window to win big immediately. The Chargers fall in the latter category.

With quarterback Justin Herbert set to play next season at the bargain cap rate of $7.2 million and not eligible for a lucrative extension until 2023, Los Angeles recognizes its window is wide open, even in the competitive AFC West division. But for the Chargers to jump through that window, they knew they needed to take some big swings, especially on defense.

"On defense, up front and then in the secondary are going to be some areas that we look at," Chargers coach Brandon Staley told reporters at the NFL scouting combine. "The goal of this offseason for us is to become a complete team and a deep team. Those two words you're going to hear me say a lot."

In 2021, the Chargers had the third-cheapest defense in the NFL based on cash spending ($66.4 million), with the Atlanta Falcons and Houston Texans lagging. The result was a team that finished 9-8 and was a field goal away from making the postseason.

At the center of the Chargers' shortcomings was a defense that allowed 27 points per game, which ranked 29th in the NFL. They struggled to cover, couldn't stop the run, failed to consistently get off the field on third down and finished 26th in Football Outsiders' defensive DVOA.

Enter Mack and Jackson.

Mack will provide a dangerous running mate for defensive end Joey Bosa to get after quarterbacks, while Jackson joins a young secondary that already features star safety Derwin James Jr. and emerging young cornerback Asante Samuel Jr.

If Jackson can pick up where he left off in New England, he offers the Chargers a playmaking man cornerback who should get plenty of takeaway opportunities with Mack and Bosa forcing quarterbacks to get rid of the ball quickly.

Over the past four seasons, no player in the NFL has more interceptions than Jackson's 25, a total that is tied for the most by any player in his first four NFL seasons since the 1970 merger, according to ESPN Stats & Information research. Last season, the Chargers had seven interceptions as a team. Jackson had eight.

The Chargers also allowed a 72.8 QBR on passes outside the numbers in 2021, third worst in the league. Jackson's passer rating allowed (42.0) as the nearest defender is also the lowest in the league since 2018, per NFL Next Gen Stats.

Now, the Chargers have the key pieces in place to take a significant step forward defensively, which should also mean meaningful progress for the team at large. They also still have room to make more moves and the No. 17 overall pick in April's NFL draft.

And while there's always the chance the Jackson signing and/or Mack trade won't pan out as the Chargers hope, it's a worthwhile swing to take for a team that can't afford to fall behind any further in its home market or in the increasingly difficult AFC West.