RENTON — The entire league passed on Richard Sherman in April.

Every team passed him over a few times, in fact, as the cornerback from Stanford was not chosen until the Seahawks picked him in the fifth round of the NFL draft.

That's nothing compared to Brandon Browner, who spent four years playing in Canada and had three tryouts with Seattle before the Seahawks signed him earlier this year.

But it has become hard for anyone to pass on them now that they are Seattle's starting cornerbacks, two bookends in a secondary that defensive coordinator Gus Bradley rated as more than just a pleasant surprise.

"Very, very pleasant," Bradley said. "We put a lot on those guys."

And they're getting plenty in return, as Seattle's eight interceptions in the past four games demonstrate.

The biggest change in the Seahawks' defense has come in the secondary, which speaks to not just the height of the 6-foot-4 Browner and 6-3 Sherman, but the impact of Kam Chancellor, a cleanup hitter of a strong safety; and Earl Thomas, the free safety with a center fielder's range.

They compose one of the youngest units of one of the youngest teams in the league. None of Seattle's starting defensive backs has more than two years of NFL experience. All are under contract through at least next season, and there is no reason to think that the group will do anything but get better.

"Everybody is developing that swag, that confidence," Chancellor said. "Just feeding off one another."

The Seahawks have rated among the league's worst defensive backfields for three years running (or, more precisely, passing). Seattle allowed the most passing yards of any team in 2008, third-most in 2009 and improved to sixth-worst last season.

This year, Seattle ranks 20th in passing yardage, still below average, but anyone who has watched this team can see the difference in the way its defensive backs are playing.

They are more physical, they are aggressive to the ball, and a team whose cornerbacks for years seemed content to keep opposing wide receivers in front of them is now getting up and challenging opponents.

The Seahawks' secondary has the height to be mistaken for a basketball team, and to put it in basketball terms, the players extend their defense the length of the floor.

"We're playing more press, and it requires guys with greater length," Bradley said.

When the season started, one of the biggest questions was the lack of experience in the secondary. But after Marcus Trufant and Walter Thurmond went down with season-ending injuries in consecutive weeks, Sherman stepped in and showed the depth of improvement the Seahawks have made in their roster.

"From the first time he went out there, he's really played well for us," Bradley said.

This is just Sherman's third year at cornerback, but he is making it difficult to believe that so many cornerbacks were chosen ahead of him in this year's draft.

"There's not 23 corners in this league better than me," said Sherman, a former wide receiver.

It's becoming hard to argue against that. And at some point, people are going to stop explaining the success of the Seahawks' secondary by pointing out the shortcomings of the opposing quarterback — whether it's Baltimore's Joe Flacco failing to complete a pass longer than 19 yards or Philadelphia's Vince Young being picked off four times.

At some point, people will point to the secondary as the primary improvement of this young Seahawks team.

"I feel like if everybody is on the same page," Thomas said, "and everybody has got the same attitude, (and) we all want the same things, then age doesn't matter."

Notes

• Seahawks MLB David Hawthorne (knee) and DE Raheem Brock (calf) missed practice Friday for the second consecutive day.

• Rams QB Sam Bradford (ankle) and A.J. Feeley (thumb) did not practice, leaving third-stringer Tom Brandstater taking the repetitions for St. Louis.

Danny O'Neil: 206-464-2364 or doneil@seattletimes.com.

Seattle's pass defense has improved as the year progressed, a positive sign for what has been the soft spot of this defense the previous three years.

/First 6 games/Last 6 games

Passing yards/250/222.3

Completion percentage/65.5/59.9

Interceptions/6/10