It is about, Derek Barnett says, "cleaning up little things" in his game and that's what he works on every day in practice leading up to gameday. The Eagles' first-round draft pick, No. 14 overall, Barnett has yet to record a quarterback sack leading some to wonder how he has performed in four games.

The truth is, he's played like a rookie: Some good and some not as good.

"He's had his ups and downs as a lot of rookies have had, or sort of have in general. I thought he was - he played an improved game against the Chargers, as opposed to the week before. He was a factor in the pass game," said defensive coordinator Jim Schwartz on Tuesday. "Made a great play on that draw. That's a hard play to defend and he made a play on the draw for a (loss of 4 yards).

"He's had very few missed assignments. I don't want to give gold stars for that because that's what's expected of us, but I think that's also a good sign coming from a rookie that's getting significant playing time, particularly in some key situations."

Barnett has played in 40 percent of the team's defensive snaps, 97, and he has recorded six total tackles, one tackle for a loss, two quarterback hurries, and a fumble recovery that came last week to end the Chargers' first drive.

In this case, maybe the numbers really don't matter. Barnett plays with high energy and has been able to command some attention. It's just that the player who broke Reggie White's quarterback sack record at the University of Tennessee and then had two sacks in his preseason debut and another the week after raised expectations for some that he might just keep 'em coming every week in the regular season.

That hasn't happened, but Barnett is not stressing. And he's not pressing.

"I'm learning every day. I'm improving. I know that," Barnett said. "I get better each and every day and the next step is to go out there and make it happen. I have a great attitude and I'm learning from my mistakes."

Barnett has mixed nicely into the defensive end rotation, giving the Eagles a deep group that includes Brandon Graham, Vinny Curry, and Chris Long. Sometimes, it's not just about sack numbers. Quarterbacks are making a point of releasing the football quickly to take the starch out of the Eagles' pass rush.

While it's working to reduce the sack numbers, the Eagles' defense is succeeding in harassing quarterbacks, hitting them, and making them uncomfortable.

"I might not be getting the sacks, but if I'm still getting back there and getting him off his point, it's helping," Barnett said. "Like Chris (Long) says, 'Keep working, doing the right things that coach wants you to do, everything else will fall into place by the end of the year.' Right now, that's my mindset. Keep on going."