By Joseph Santoliquito

PHILADELPHIA, PA (CBS) — There is a steely-eyed demeanor about Eagles’ first-year defensive backs coach Cory Undlin. He knows the issues the Eagles’ secondary had last year.

Philadelphia ranked 31st in the NFL in pass defense in 2014, giving up a total of 4,238 yards passing. The only team worse was Atlanta, which gave up 4,478 passing yards. Compounding that was the fact that the Eagles gave up 72 pass plays that went for 20-plus yards, the most in the NFL (Chicago came a distant second at 65), and 18 plays of 40-plus yards, another NFL high.

Undlin obviously wants to change that this year, starting with starting cornerbacks Bryon Maxwell and Nolan Carroll, along with safeties Walter Thurman and Malcolm Jenkins, with more press coverage.

“From what I know in my time here, yes, we will press more,” said Undlin, who comes to the Eagles after coaching in Denver, where he helped develop three Pro Bowl defensive backs (Aqib Talib, Chris Harris Jr. and T.J. Ward). “The defense is predicated on that. We don’t play just straight man coverage, but we play a lot of coverages where our guys will be out there hopefully getting their hands on people. I would say the biggest difference between the corners they had last year and who we have this year is technique. We work on it every single day. If you’re going to come up in press coverage, you have to make it sound. We’ve been working on it a lot.

“One of my philosophies is when teach football, when the player buys in, he wants to work at it and wants to become a craftsman and work on that technique, they can get better. My emphasis has been playing up at the line of scrimmage. Now listen, we can line up and not put a hand on anyone. I think they’ve all gotten better in their press coverage. Are we there yet, perfect, no? We still have work to do. We all got better.”

Undlin has also liked the improvement Thurman has made, making the conversion from cornerback to safety. Undlin likes how fast Thurman thinks and how quickly he absorbs information. He also trusts Thurman’s ability to make open-field tackles.

“We talk about tackling, we talk about tackling and leverage,” Undlin said. “If Walter is in a deep part of the field and someone is running up on him, he has 20 yards of space, something is drastically wrong. Thurman has great awareness and he’s a good tackler. Just get the guy on the ground. I don’t need anyone blowing a guy up. Just get the guy on the ground. I feel very, very strongly he will do that.”