ASHBURN, Va. -- The Washington Redskins have altered their mindset and returned to an old-fashioned philosophy. They want to be physical in the run game; they want to play sound defensively. It’s one reason they’re an even 2-2 through four games, which represents growth for a franchise in need of some.

There’s a lot to build on: the running game; signs of growth at quarterback and an improved defensive front. They have young players contributing and arguably the best offensive line coach around.

But they have an equal amount of areas they must improve if they want to keep having success. Here are some areas of lingering concern:

Secondary play

The Redskins are committing more players in coverage than in the past, relying on a quality four-man rush to prevent big plays. They've blitzed 18 times this season -- they blitzed 22 times alone in the final two games of 2014, according to ESPN Stats & Information. The problem is, the rush isn’t always producing, whether because of quick passes or slower-developing rushes, and the big plays have still happened. They’ve allowed at least one 40-yard catch in each of the past three games and have four overall, putting them on pace to surpass last year’s total of 12 such plays.

It doesn’t help that Chris Culliver has a sore knee; his play suffered because of it against the Eagles. But he also must rely more on safety help and that’s been a problem. Will that change? Trenton Robinson has a lot to learn, but the question is will he do so? And, if not, who replaces him? The Redskins signed Jeron Johnson to be a starting safety but he was beaten out by Duke Ihenacho and then Robinson. They also have Kyshoen Jarrett, but he’s playing slot corner for now and he was still learning the free safety spot. They need their safeties to be interchangeable, which is why that’s important for Jarrett.

Injuries

This area has hurt the secondary as a group without a lot of depth has been tested in that area early. Since camp opened, there has been one issue after another with the secondary when it comes to injuries or suspensions. But Ihenacho and Justin Rogers already are on injured reserve and DeAngelo Hall will be sidelined another two to three weeks with a toe injury. But it’s not just this group as the Redskins have 10 players on injured reserve, at least seven of whom would have been contributors and four who were starters. They ended last season with 12 players on injured reserve.

That takes a toll and it can be felt on special teams the most. They’re now using more inexperienced players in this area and that leads to mistakes such as Quinton Dunbar, playing his first game, hitting a punt returner who had called for a fair catch. It also leads to broken lanes in coverage, leading to long returns.

Turnovers

This category matters as much as any and when you learn that the Redskins are minus-24 in turnovers since the start of the 2013 season, then it’s no surprise that they’re 9-27 during that time. They’re 5-4 in that time when they finish with a positive turnover margin and 4-23 when they don’t. In fact, they’ve won one game in their last 36 when they’ve had a negative turnover margin. Look at those numbers again; it's eye-popping. Quarterback Kirk Cousins has thrown four interceptions and needs to get under that one per game average, unless he’s throwing two touchdown per games (right now, it’s one per game as well).

This season, Washington is minus-4, and that’s because of what both sides of the ball have or have not done. The Redskins have turned it over seven times, tied for 20th in the league while forcing only three turnovers, tied for 24th. If they at least take care of the ball it’s a start. But the defense must start forcing more as well.

Penalties

Another troubling area because the Redskins just don’t have much margin for error. The Redskins have committed 35 penalties -- only four teams have more. It’s not like penalties ruin seasons as Green Bay has one more penalty than Washington and Cincinnati has the same amount as the Redskins. Both teams are 4-0. But one team has the NFL’s best quarterback and the other has a stout defense (ninth in the NFL in scoring defense at 19.2 points per game) and a plus-three turnover margin. To have a negative turnover margin and commit a lot of penalties? It’s a bad way to sustain any success. They beat Philadelphia Sunday despite 10 penalties. But only one turnover and one sack in 46 pass attempts compensated. But it’s a hard life to live.