The Chargers looked like they were going to be a playoff team in 2021. The team had an 8-5 record through 13 games and was armed with one of the best offenses in the league.Justin Herbert, Keenan Allen, Mike Williams and Austin Ekeler formed a quartet of excellent offensive weapons. Add in the fearle s play-calling of coach Brandon Staley, and it Chris Baker Jersey seemed like the Chargers were a threat to score on every po se sion.However, the Chargers weren't able to make the playoffs last season. They faltered in the final month of the season, losing three of their last four games, and that was largely thanks to some i sues they had on defense.MORE: Los Angeles' defense wasn't in 2021, but it had its share of warts. During the final four games of the season, the Chargers allowed at least 34 points in three of their outings and surrendered an average of 30.75 points per game. That included them allowing 41 points to the lowly Texans in Week 16.The Chargers knew they had to do something to upgrade their stop unit, and they did. General managerTom Telesco spent plenty of resources on that side of the ball to ensure that Los Angeles won't have as many i sues as it did try to stop teams in 2021. That will give them a well-rounded team given their explosive offense.How did the Chargers upgrade their defense? Below is a breakdown of the major moves they used to give themselves a chance to compete for the AFC West title. The Chargers wanted to add a fearsome complement to go with Joey Bosa on their defense. So, on March 16, 2022, Los Angeles sent a 2022 second-round pick that became Jaquan Brisker and a 2023 sixth-round pick to the Bears in exchange for Khalil Mack.Mi sion accomplished.Mack was coming off a year during which he played a career-low seven games but still logged six sacks. The Bears needed to clear his cap number from the books, so they moved on from the 31-year-old. That should benefit the Chargers greatly.NFL TRADE GRADES: Mack was a stud in his first game in Los Angeles. He recorded three sacks against a helple s Raiders offensive line, but he actually thought he should have been better during the contest."It wasnt good enough," Mack said after the Chargers win, per . "I left a Bobby Hart Jersey lot of stuff out there and I have to get it corrected."Mack may feel that way, but it was clear that his presence had Drew Sample Jersey an impact on Los Angeles' defense. He opened up a lot of lanes for his teammates, including Bosa. Bosa's presence does the same for Mack, but it's their communication that could be a real a set for the Chargers."Its great to talk ball on the sideline and just communicate about what we get and what each offensive tackle is giving us," Mack explained. "So to bounce ideas off each other throughout the game is good."It's early, but the Chargers paid relatively little to get Mack and are already getting ma sive production out of him. That move could be the one that takes their defense to the next level.MORE: (Getty Images) The Chargers have had strong cornerback play in recent years, but they were lighter at the position in 2021 after Casey Hayward joined the Raiders. As such, the team needed to add more to the position in 2022, especially with Chris Harris set to be a 33-year-old free agent.Signing Jackson was a great move to shore up that position.The New England ballhawk known as "Mr. Interception" was available in free agency, and Los Angeles signed him to a five-year deal worth $82.5 million to be the team's top cornerback.Jackson has logged a whopping 25 interceptions during his four-year NFL career. That includes 17 over the last two seasons. He made the All-Pro second team in 2021 and led the NFL in pa s Jake Fisher Jersey defenses with 23.The Chargers had just 11 total interceptions last season. That was tied for the eighth-fewest in the NFL. Jackson had eight by himself, so Los Angeles will have far more splash play upside on defense with him in tow.Jackson could be the final puzzle piece n the Chargers' secondary. He will allow Michael Davis and Asante Samuel to slide into the more natural No. 2 cornerback spot and provide the team with great depth on the outside.So, between Jackson's coverage ability and Mack's pa s-rushing skills, it will be much harder to throw against the Chargers than it was in 2021.POWER RANKINGS: Mack and Jackson represented the star power acquired by the Chargers during the offseason. However, they added plenty of other key role players that will bolster their stop unit and provide the team with plenty of depth something they didn't have last season.Below is a breakdown of each move and how it helped the Chargers. (Getty Images) DT Sebastian Joseph-DayThe Chargers were gashed by Rex Burkhead in their Cordy Glenn Jersey Week 16 defeat at the hands of the Texans. Burkhead ran for 149 yards and two touchdowns on 22 carries, and in that moment, it became clear that Los Angeles needed to add some run stuffers to their defensive line.Joseph-Day qualifies. He's a 6-4, 310-pound defensive tackle and has consistently ranked as a solid run stopper, per Pro Football Focus. He had 22 stops in 2021 and 33 in 2020, so he should be able to help the Chargers contain the run better this year than they did last year.Joseph-Day came over from the Rams, so he has experience working with Staley. That should make his transition as a key role player relatively smooth.DT Austin JohnsonJohnson was brought in for the same reason as Joseph-Day. He's big (6-4, 314 pounds) and will be a strong run defender for the Chargers.Johnson is coming off a season that saw him make 72 combined tackles and register 3.5 sacks. Both are career highs. He should do better with the Chargers than he did with the Chargers considering the talent surrounding him.In Week 1, Johnson made one tackle and generate one pre sure while playing just over 50 percent of the defensive snaps. He graded out as PFF's 19th-best defensive lineman out of 123 in that contest, so his impact went beyond the box score stats.FANTASY:CB Bryce CallahanJackson wasn't the only corner the Chargers added to the fold. They also brought in Callahan, who was once one of the better slot cornerbacks in the NFL.Callahan has struggled to AJ McCarron Jersey stay healthy in recent seasons, as he had only started 16 games since 2019 entering 2022. However, he looked good in the slot for Los Angeles in Week 1, as he made five tackles and logged an interception and two pa s defenses during the contest. Both of the latter numbers are tied for the NFL lead after one week.It's unclear whether Callahan will continue to start in the slot when Jackson returns from injury, but either way, he has helped shore up the depth in Los Angeles' cornerback room. They now have four players capable of starting, so they can mix and match depending on the matchups they like. OLB Kyle Van NoySince his first full season with the Patriots in 2017, Van Noy has averaged 56 tackles, six sacks, five pa s defenses