Redskins.com's Stephen Czarda provides five things we've learned about the Washington Redskins through the first four games -- Eagles, Rams, Raiders and Chiefs -- of the 2017 regular season.

1, The defense is looking like a completely different unit this year.
One season after the Redskins finished 28th in total defense, the unit looks anew this season under Greg Manusky, who was promoted to defensive coordinator in the offseason after spending the 2016 season as the team's outside linebackers coach.

Through the first four games of the season, the Redskins rank 10th in total defense allowing just a little more than 311 yards per contest. Washington also ranks third in the NFL in total sacks (12) while allowing just 69 first downs.

Washington's best defensive performance in 25 seasons came in a 27-10 victory over the Oakland Raiders, as the defense allowed just 128 yards – the fewest yards allowed by Washington in a game since Oct. 12, 1992. They also didn't allow Oakland to convert on all 11 of their third down plays.

"I think we played very strong in the middle of our defense," said Redskins head coach Jay Gruden. "Our defensive linemen did a great job being stout. Our outside backers were stout in the running game and held them to minimal yards per carry and forced them to throw the ball in known passing situations, enabled our rush to get home and our coverage was tight. I think just all around, the calls were sound, the players executed, we tackled extremely well, we flew to the football, didn't give up any big plays whatsoever – other than the touchdown pass after the turnover.

"I think when you're talking about a defense that played that well, I think it's impossible to just say, 'This is why.' I think it's because everybody who took part played well, played hard, played with great passion and energy and played smart."

This success is also coming with linebacker Trent Murphy and defensive lineman Phil Taylor – both of whom were expected to be key rotational players – sidelined for the year with injuries and the team having to quickly determine a new strong safety plan when Su'a Cravens was placed on the Reserve/Lefft Squad list.

The unit's depth was tested against the Kansas City Chiefs, as numerous players including cornerbacks Josh Norman and Quinton Dunbar along with safeties Montae Nicholson and Deshazor Everett were all sidelined for certain periods of time with injury.

"Everybody can play on this team, it's not like a big drop-off, everybody can play and that's how Manusky coaches it," said linebacker Mason Foster, who sealed Washington's Week 2 victory over the Rams with a late interception. "So everybody's got to be ready and I think guys prepared throughout the week and they were ready when they came onto the field."

2. Vernon Davis continues to be "The Ageless One."
For most teams, having their No. 1 tight end limited would be troublesome. But the Redskins aren't like most teams in the NFL with the depth they have at the position.

With Jordan Reed has been slowed by various injuries so far this year, Davis has stepped up in a big way for the offense.

After not being targeted in Washington's Week 1 loss to the Philadelphia Eagles, the 33-year-old has caught eight passes for 160 yards – 11th most among tight ends – and one touchdown. His 20 yards per reception also leads all tight ends.

In the Redskins' blowout victory over the Raiders, Davis caught a 22-yard touchdown pass in the second quarter. Then against the Chiefs in Week 4, Davis caught two passes for 89 yards – 69 of which came when Davis outran two defenders to initial catch the ball before weaving his way through traffic.

"He's the most impressive guy I've been around really as far as taking care of his body, and whatever he's doing, he needs to tell all our young guys to do it because he's amazing," Gruden said. "Just out here [at practice], he's running around like a 20-year-old kid. We're going to have to try to dive into that but I know he has a great routine in the offseason, during the season. His diet is top-notch. His workouts are on point. Not to mention he prepares and he's just always got a smile on his face. He's just one of those guys you look forward to seeing every day and then you watch him practice and it's always hard and effective. Great guy, great player."

Quarterback Kirk Cousins added that Davis has earned the nickname "el caballo" because "he's like a thoroughbred the way he runs down the field."

"We always talk about his hamstrings and how they're like the hamstrings of a 19-year-old," Cousins said. "Special player, but I keep going back to he's a great player, but he's a better person. He's not a guy who acts entitled. He's a guy who could at his age and experience level. He is just very humble, hungry and is just a fun guy to play football with."

3. New faces have led the way for the defensive unit.
One of the reasons why the Redskins have seen such positive early returns on the defensive side of the ball is because of some of the players that were brought in this offseason.

Yes, Ryan Kerrigan and Josh Norman continue to play at a high level. Matt Ioannidis also looks like a completely different player this year, too.

But the likes of D.J. Swearinger, Zach Brown and Jonathan Allen have made a difference.

After an offseason competition for the starting inside linebacker spots, Brown earned the nod to be the No. 1 Mo linebacker and he hasn't disappointed.

The 2016 Pro Bowler currently tops the NFL in tackles with 42.

"I think his speed really shows up on tape," Gruden said. "Plays that… for instance, the Rams game, when the kid broke a long run – the tight end who ran a 4.5 at the combine or whatever he ran – he got hawked down by Zach Brown, and what the heck did Zach Brown run then? So his speed shows up a lot. Pursuing to the football, dropping in pass coverage, planting his foot and coming and gang tackling and making plays, so I think you don't really notice that on the practice field until you get in game day when you see it show up. I think that's the biggest thing that he's added to this defense – he's added to our team speed."

Swearinger, meanwhile, is a vocal presence in the defensive backfield. But his presence goes well beyond the lines.

He's recently hosted a players-only "Get Right" meeting to focus on corrections.

"I emphasize all the small things. Sort of the small things that coaches don't cover that experience has to give you," Swearinger said. "That's what I try to give them. They're growing. Shazor [Deshazor Everett], he's doing great. Montae [Nicholson] is doing great. Those guys, I'm a young guy but I feel like I'm an old guy with these young guys. I feel like a proud big bro, especially with Montae and Shazor but I'm going to stay on those guys and they're going to continue to get better."

As for Allen, Washington's first-round pick in this year's draft has been productive in the trenches. He continues to lead the defensive line's rotation as he grows with every passing week.

"That's the beauty; that's the most exciting thing about Jonathan. He just hasn't scratched the surface of his own potential yet," Gruden said. "He is just going to get better and better the more he sees and the more he plays."

4. Chris Thompson has been one of the league's breakout players so far.
Entering the season, Gruden remained committed in his belief that Thompson is one of the best third-down backs in the NFL. Then the Redskins remained committed in their belief that Thompson should remain in Washington for a few more years, as they signed him to a contract extension before the regular season opener.

Through the first four weeks of the season, the 2013 fifth-round pick has recorded 20 carries for 142 yards and two touchdowns along with 14 receptions for 235 yards and two receiving touchdowns.

Thompson is just one rushing yard off from leading Washington in both rushing and receiving.

"I think the temptation early on was, 'Man, he's a little small-ish. Can he hold up? How much can you give him the ball, how much can you play him?' He was a big part of special teams. But then when he's on the field, he's so productive in every phase of the game," said Redskins offensive coordinator Matt Cavanaugh. "He's a good runner, very good runner. He's got great explosion. He's excellent in running routes and catching the ball, and he's a very good pass protector."

Against the Eagles in the opener, Thompson recorded the Redskins' first touchdown of the season when he caught a short pass and flipped it into a 29-yard touchdown off a magical play. The next week, he logged two more touchdowns against the Rams before accumulating 188 yards from scrimmage against the Raiders.

While there's certainly a temptation to get Thompson more and more reps, Gruden wants to keep his role – one that he's excelling in – defined.

"I've said before, he's a very valuable guy in the role that he's in – third down," Gruden said. "He's also one of our kick returners. He does a lot of getting back on track calls on second down-and-long, and there's some first-down plays that he's in. But, yes, it's important for us to keep him healthy. He's not a guy that I personally want to give him 30 carries a game. He probably wants it but he probably won't get it."

5. After one of his worst outings in the opener, Cousins is starting to round into form again.
It was a game in which the Pro Bowl quarterback didn't look himself.

Coming off a season in which he threw for nearly 5,000 yards, Cousins struggled against the Eagles in Week 1. He completed only 23-of-40 passes for 240 yards with one touchdown to one interception.

The interception was one of three turnovers from Cousins, as the quarterback skied an errant pass on a crucial third down throw. Then minutes later, the quarterback was stripped sack as he was trying to mount a game-winning drive.

But in the three games since the opener, Cousins has been nearly flawless.

Along with leading a successful game-winning drive against the Rams, Cousins was named NFC Offensive Player of the Week for his efforts against the Raiders (25-of-35 for 365 yards with three touchdowns).

In total against the Rams, Raiders and Chiefs, Cousins is 57-of-81 for 764 yards with six touchdowns to no interceptions.

"I think there is a lot to like, really, I think especially after the first game," Gruden said. "He got a lot of pressure. He was a little bit inaccurate the first game, more so then he ever has been but a lot of that had to do with the pressure that Philly gave him. People were in his face quite often. I think he has improved dramatically Week 2, Week 3 and even [against the Chiefs]. I was impressed that last drive. He had a couple huge scrambles using his legs, big runs to get us into a position to get a tying field goal or possibly win the game if Josh can hang on to the ball.

"Kirk is playing well and he is getting us in position to win. That's all you can ask for at the end of the day. …I have been impressed with Kirk in the way he has come on after Week 1."