FOXBOROUGH, Mass. – What type of team are the New England Patriots facing when the Los Angeles Chargers visit Gillette Stadium on Sunday (1 p.m. ET)?

ESPN.com NFL Nation Chargers reporter Eric Williams has had things blanketed all week, and continuing a season-long theme of sharing insight of NFL experts familiar with the Patriots’ next foe, former Chargers offensive lineman Nick Hardwick shares his thoughts on the Chargers. Hardwick played for the Chargers from 2004 to 2014 and currently hosts a radio show on Xtra 1360 in San Diego and provides analysis on Fox 5 in San Diego.

He follows NFL experts Trent Green (on the Chiefs), Bobby Hebert (on the Saints), Ted Johnson (on the Texans), Steve Israel (on the Panthers), Ira Kaufman (on the Buccaneers), Marty Lyons (on the Jets) and Dave Archer (on the Falcons) in the series.

Here's Hardwick on the Chargers:

Melding of systems has produced sweet spot: “Right now, they are a team that just recently found their identity. They were kind of butting heads, it seemed, between two offensive systems to try to figure out what they would be -- melding together [head coach] Anthony Lynn’s ground-and-pound, sort of old-school ‘Marty Ball’ system with [offensive coordinator] Ken Whisenhunt’s ‘11 personnel’-shotgun-spread-and-throw-all-over system. It started in New York [against the Giants] a couple weeks back, pounding the ball, being patient with the running game. It hasn’t been wildly successful, but it has shortened games, kept games close, and they’ve counted on their defense and done a much better job stopping the run and keeping teams out of the end zone. And the kicking game has held up its end of the bargain after they let go of Younghoe Koo. So they’ve played the field-position game, put Philip Rivers in a tighter-decision-making [situation] and are relying less on him to make every play.”

Stopping the run has been a work in progress: “They lost middle linebacker Denzel Perryman to ankle surgery, and he was their one hit-and-quick type of guy. They’ve had a rotating cast of characters in there: Hayes Pullard from Jacksonville; Korey Toomer, but he wasn’t active one week; Nick Dzubnar was in there. They were able to stop the run last week, which was the first week they had a lot of success with it. It was a game against Denver where both teams knew the game would come down to whether the Chargers could stop the run because they wanted to put all the pressure on [Broncos quarterback] Trevor Siemian. They fired out in their run fits, had gap control, and you could see they were starting to trust the guys in front of them and behind them to take care of their responsibility and the understanding of what [defensive coordinator] Gus Bradley is looking for. The football IQ is starting to increase. [Bradley is] a really good teacher, so you expect increased performance throughout the season and they’ve done that.”

Undrafted free-agent CB from 2016 catches eye: "They lost cornerback Jason Verrett, a former Pro Bowler, and Trevor Williams has come in; an undrafted player in his second year with the team and he’s been very sharp. I don’t want to say he’s playing at a Pro Bowl level, but when you watch the film, you don’t notice him. For me, a cornerback is like an offensive lineman -- if you don’t notice him, he’s doing a good job."

Adjusting to injuries on the offensive line: "Left guard Matt Slauson tore his biceps and is on IR, which means third-round pick Dan Feeney of Indiana steps in. He had been playing center and right guard in preseason, and was sprinkled in wisely by the coaching staff [in the regular season], which gave him some game reps before anything happened [to other players injury-wise]. With Slauson there is technical acumen and toughness, but probably more than anything, they’ll miss his intangibles and calming presence, the leadership he brought to the huddle. He’s been around the NFL, played every top defensive tackle, and he’s a leader. Feeney brings really good athleticism and is more explosive than Slauson, but you have to watch how he handles matchups across the board. We know Bill Belichick is really big on the diamond defense, which means offensive linemen are asked pretty repeatedly to perform one-on-one in pass protection, and [Feeney will] have to withstand that over the course of the game.”

Dynamic pass-rushing duo of Melvin Ingram and Joey Bosa: “They are really fun to watch. Ingram and his maturation -- going from a young, kind of chunky outside linebacker to a grizzled, hardened, wildly explosive ‘Leo,’ which is what they call him -- a defensive end/edge rusher with the ability to get compact and explode into offensive linemen, running backs and quarterbacks. It’s really exciting. It’s not just athleticism, not just stringing together all those pass-rush moves, but situationally he understands the game even more now, which means the capability to process personnel groups, attacking offenses, knowing how they are planning to protect against him and Bosa. So you’ve seen the maturation as a football player; he’s always had the athleticism and after getting a big contract, he could have gotten lazier but he’s only gotten hungrier. Bosa, if he can somehow bring Tom Brady down -- which is a huge challenge -- he’ll set the record for most sacks in a player’s first 20 games in the NFL. The veteran look of his game is staggering for a player his age. It’s unbelievable. You’re talking about seventh- and eighth-year techniques. The thing I like the most is how he’s understanding offensive line technique and how they’re trying to attack him. He’ll engage, then discard your hands and work the edge in that fashion. It’s second- and third-level stuff. His game isn’t flashy like J.J. Watt, with that type of jump-around ability. It’s more Mike Myers from Halloween – he’ll stalk you down, hunt you methodically. He’s indefatigable.”

Keys for the Chargers to win: “Find a way to sustain drives. They’ve had a difficult time doing that this year. Two weeks ago, they were 70 percent run on first down and had some success with it … If you allow Tom Brady and that offense to be on the field, they will sustain. They’re built for it, to stay on the field for 9, 10, 12 plays and wear a defense down. So the Chargers offense has to stay on the field and play keep-away. That means running the ball, being effective with the play-action pass, and on third down. Show a little creativity and make adjustments. You know a Bill Belichick defense will take away who they perceive to be your top two targets. So you have to find a way, mid-game, to assess who they are targeting and make the proper adjustments and go to the other guy. The Chargers have plenty of weapons to do that. One other thing: Believe you’re a real football team. They’ve won three in a row and now they’re stepping up in the big-boy world, against the defending champions at home. It’s a mental game as much as a physical game. So having confidence in what you’re doing, and don’t try to do too much.”