First there were Quintin Mikell and Sean Jones in Sean McDermott's Jim Johnson-cloned defense. Then there were Mikell and Nate Allen. Then Allen and Kurt Coleman for two years behind the "wide nine." Then Allen and Patrick Chung in Bill Davis' completely new scheme. And then Allen and Malcolm Jenkins last year.

Interspersed as starters in that six-year span have been Macho Harris, Colt Anderson, Jarrad Page, Jaiquawn Jarrett, David Sims and Earl Wolff.

It's been seven years since the Eagles and Brian Dawkins parted ways, and for the first time since his departure, the team has two more than competent safeties and a scheme that matches their skill sets.

Jenkins was effective for most of last season, but he is playing at a career-high level in an expanded role. Complementing him has been Walter Thurmond, who never played safety until this year, but has stepped into the role as if he were a veteran.

They have factored prominently into the Eagles' improvement on defense. The defensive line receives the bulk of credit, as it should. And linebacker play hasn't been too shabby, either. But Jenkins and Thurmond's steady performance at safety has solidified a secondary that weighed the unit down the previous two years.

The back end isn't without its faults, but the numbers support what has been visible through six games. The Eagles defense is fourth in the league in passing yards per play, third in rushing yards per play, second in turnovers, and sixth in points allowed.

Talent or lack thereof was the No. 1 reason the Eagles struggled at safety "A.D." (After Dawkins). They made poor decisions in free agency (Jones, Page) and poor evaluations in the draft (Allen, Jarrett). But scheme also played a part.

Allen wasn't the run-stopping safety that the wide nine alignment required. He also wasn't versatile enough to play behind Davis' two-gap, 3-4 front. The same went for Chung, who has fared well in the Patriots defense since his release two years ago.

But in Jenkins and Thurmond, both former cornerbacks, Davis has a combo that suits his system. His safeties are asked to help against the run, but they don't have gap responsibility, as safeties often have in one-gap, penetrating 4-3 defenses.

"When I teach a base 4-3, a lot of times I need a safety that can handle the run game," Davis said on Wednesday. "So you have a Dawkins - safety-linebackers. With a two-gap system we'll take it even into our nickel. I don't have to give those guys the big boy gaps."

The Eagles aren't the only NFL team to convert corners into safeties. It has been happening for years, but increasingly so at a position scarce on talent in the college ranks. But Jenkins and Thurmond's corner backgrounds have allowed Davis flexibility in his scheme, particularly on passing downs.

So Jenkins can play in the slot when the Eagles are in their nickel and dime packages. And Thurmond can float in the secondary and make plays as Chris Maragos mans the center-field safety spot.

Jenkins played some slot last season in the base defense, but Brandon Boykin's departure via trade paved the way for a nearly full-time role there. He has excelled. He has lined up there for 136 routes and has allowed only 14 catches for 108 yards.

But his greatest value may be in how he quarterbacks the secondary. Everyone communicates, but Jenkins directs traffic even when he's in the slot, which isn't typical.

"Malcolm is by far the most dominant personality back there in terms of making calls," Davis said. "He loves that role of making the decision."

Jenkins spends an inordinate amount of time watching film, but so do many players. What separates him from others, Davis said, is that he is able to bring that knowledge to the field and get the defense in and out of coverages as an offense shifts.

"Guys with good football IQs have the original call down and when movement happens we can get to the next call. A they're like this," Davis said as he snapped his fingers.

Nolan Carroll's interception for a touchdown against the New York Giants on Monday might not have happened, according to Davis, had Jenkins not yelled for the cornerback to switch off to the outside receiver.

Thurmond can jump down into the slot and also can assist against the run, but he has been most effective in the middle of the field. All three of his interceptions have come when he has read the quarterback's eyes and jumped a route.

"I feel like I've always been able to do that. I just had never been put in those positions," Thurmond said. "Just being able to fly around during [the spring] and training camp, they were able to see my ability to have that knack for the ball."

Davis said that Thurmond still offers to play outside corner. He said he hopes someday to have that flexibility. Jenkins called Thurmond "probably the most versatile player I've played next to."

They feed off each other.

"He looks to me . . . because this is his first year playing safety," Jenkins said. "Just some of the things that I know I can teach him, he learns from me. And then there are things that he naturally does that I try to pull from him. And then we're constantly competing against each other to see who can make the most plays."

Right now, they're neck and neck. How long has it been since the Eagles have been able to say that about their safeties?

jmclane@phillynews.com

@Jeff_McLane