To get you ready for the 2016 NFL season, the PFF analysis crew is assembling team “cheat sheets” to catch you up on the latest changes, grades, and rankings of note involving your NFL team.

The San Diego Chargers are looking to rebound from a four-win season that earned them the No. 3 pick in this year's draft. They’ve had a strong offseason to this point, but will still have a tough time cracking through what looks to be a difficult AFC West. Even with Peyton Manning retiring, the Broncos still field a competitive defense and fearsome pass rush, while the Chiefs remain a solid team and the Raiders are trending upwards. How will the Chargers fare against their division rivals—and beyond—in 2016?

Three biggest things to know

1. The Chargers's offensive line will need to dramatically improve over last season…

The Chargers fielded the lowest-ranked offense in the NFL a year ago. The unit combined for a league-low pass-blocking efficiency after allowing 298 total pressures—77 more than any other line—in 716 passing plays, which undoubtedly contributed to Philip Rivers finishing with his lowest passing grade in the 10 seasons PFF has charted. San Diego's performance in the run game wasn’t much better; no player finished the season with a positive grade there, and Chargers’ rushers gained an average of just 1.39 yards before contact, the third-lowest mark in the league.

Fortunately, the unit has a few reasons for optimism going into 2016. First, they saw just 318 snaps from LT King Dunlap, who graded well above-average when fully healthy in 2013 and 2014. Second is the free-agent addition of center Matt Slauson, who brings an above-average career grade over seven seasons, and should be a massive upgrade over Trevor Robinson, PFF’s lowest-graded center in 2015. Retaining last season’s top performer, RT Joe Barskdale, shouldn’t hurt either.

2. … As will the defensive front-seven.

San Diego faced similar problems in the trenches on defense in 2015. No team collectively graded worse in run defense than the Chargers, while just one other team (New Orleans Saints) allowed a higher average gain per carry. Former Seahawks DT Brandon Mebane should help tremendously on early downs, even if he’s far from his 2013 peak, as will dumping underperformers Kendall Reyes and Donald Butler, which the Chargers did this offseason. LB Manti Te’o remains a question mark after missing a team-high 16 tackles and finishing the 2015 season with one of the worst run-defense grades among off-ball linebackers, but perhaps he’ll see improvement with a better D-line in front of him.

In the passing game, the team’s front-seven wasn’t nearly as bad, with pressure on roughly 36 percent of opponent’s passing plays (ranking middle-of-the pack league-wide). The bulk of that production came from LB Melvin Ingram, with Jerry Attaochu behind him, and they should benefit from the addition of third-pick Joey Bosa.

3. Replacing Eric Weddle at safety could be a major challenge.

While the team should be set at corner with Jason Verrett, Casey Hayward, and Brandon Flowers, it won’t be as easy covering the loss of Eric Weddle at safety. Weddle played 91 percent of the team’s snaps since being drafted in the second round in 2007—8,730 in total—and graded positively over all nine seasons in San Diego. Replacement Dwight Lowery has been consistently average over his career—sometimes even slightly above-average—but he’s never matched Weddle’s production. It’s also concerning that the two lowest season grades of his career have come within the last three years. Much of the onus will be on fourth-year player Jahleel Addae, who had a solid rookie season in coverage, but has graded negatively in both the passing and running game over last two years, including a career-low overall mark in 2015. Will he bounce back in 2016? Two positive grades in his first two preseason games is encouraging, albeit in a limited sample (24 snaps).

Key arrivals and departures

Top three draft picks: DE Joey Bosa (Round 1, pick No. 3 overall, Ohio State), TE Hunter Henry (Round 2, pick No. 35 overall, Arkansas), C Max Tuerk (Round 3, pick No. 66 overall, USC)

Signed in free agency: C Matt Slauson (Bears), CB Casey Hayward (Packers), DT Brandon Mebane (Seahawks), S Dwight Lowery (Colts), WR Travis Benjamin (Browns), WR James Jones (Packers)

Left via free agency: CB Patrick Robinson (Colts), RB Donald Brown (Patriots), S Eric Weddle (Ravens), TE Ladarius Green (Steelers), S Brandian Ross (Broncos), DI Kendall Reyes (Redskins), T Jeff Linkenbach (Jaguars)

Cut: P Mike Scifres, LB Donald Butler

Retired: WR Malcom Floyd

Rookie to watch

Hunter Henry, TE (Round 2, pick No. 35 overall)

With Malcom Floyd gone, Antonio Gates a year older (36), and WR Keenan Allen likely to draw substantial attention from opposing defenses, there should be plenty of opportunity for the FBS’ highest-graded TE in the passing game last season. Henry didn’t drop a single pass while gaining 2.36 yards per route run during his final season at Arkansas, a figure that ranked in the top-five among his peers, and would have been second among NFL tight ends, just behind Jordan Reed’s 2.45 mark.

Through his first 44 preseason snaps, Henry has looked the part, hauling in four of five targets for 50 yards. His run blocking has been below-average, but that’s not necessarily surprising for a rookie seeing his first NFL action, and it wasn’t a strength in college. It’s the passing game where he’ll have the most impact, and he should help Rivers bounce back from a career-low passing grade.

Highest-graded player of 2015

Jason Verrett, CB, 89.7 overall grade

After being drafted 25th overall in 2014, Verrett started his rookie season quite well with the eighth-best coverage grade over the first eight weeks. Injuries, however, forced him to miss the entire second half of that season. Fortunately, he was healthy for most of 2015, managing to stay on the field for 735 snaps, and picked up where he left off from his rookie year. He ended the season with the second-best coverage grade among CBs, behind only Arizona's Tyrann Mathieu, and he could be even better in 2016. Last season, Verrett had the highest percentage of coverage snaps with a positive grade, a figure that has been be fairly consistent year-to-year.

Breakout player watch

Denzel Perryman, LB

Perryman quietly had one of the best seasons of any rookie defender in 2015, although he didn’t see a single vote for Rookie of the Year. That was likely in part because he played just 65 snaps over the first 10 weeks of the season, but once Perryman actually saw consistent playing time (starting in Week 11), he was excellent. He ended the season with the fifth-highest run-defense grade (85.0) among all linebackers, and led all ILBs in run-stop percentage, at 18.3 percent. Last season, the Chargers' defense missed at least one tackle on 115 plays, but only four of those came from Perryman, whose tackling efficiency ranked fifth among ILBs—a substantial improvement over his final college season, which he finished with 15 missed tackles in 749 snaps. We’ll see if he can maintain that form in a full-time role in 2016.

Projected lineups

Base defense (2015 season grades shown)

Base offense (2015 season grades shown)