By Joseph Santoliquito

Philadelphia, PA (CBS) — There was a sense some fallout might come from Sunday’s fourth-quarter debacle against Detroit—and on Tuesday morning it did, when Eagles’ coach Andy Reid fired defensive coordinator Juan Castillo.

Secondary coach Todd Bowles, 48, who played for Temple in the late 1980s, has been named the new defensive coordinator replacing Castillo.

Reid warned on Monday at his day-after press conference to expect some changes.

It’s a monumental shakeup to the Eagles’ coaching staff, and in an indirect way, Reid admitting he made a major mistake in naming Castillo, the Eagles’ longtime offensive line coach, as d-coordinator two years ago.

“We’re six games into the season and average isn’t good enough,” Reid said in a statement. “I know the potential of our team and insist on maximizing it.”

“I want to make it clear that I have nothing but the ultimate respect for Juan Castillo as a coach and as a person. He’s one of the finest football coaches that I have ever worked with. He has served this organization extremely well for 18 years and letting him go was a difficult decision. I know he will continue to be a successful coach in this league and wish he and his family nothing but the best,” Reid said.

What did Castillo in was another squandered fourth-quarter lead, galvanized by Sunday’s disastrous fourth-quarter meltdown, losing a 10-point lead with 5:18 left in a 26-23 overtime loss to the Detroit Lions. In the two years Castillo was the defensive coordinator, the Eagles were 11-11.

The Eagles have lost seven fourth-quarter leads since 2011, the most in the NFL.

Castillo was already the hot seat entering this season. The Eagles blew five fourth-quarter leads last year, four at home, which established a dubious new NFL record. The Detroit loss rekindled more visions of 2011 when Arizona’s John Skelton threw for 166 yards in the fourth quarter in a 21-17 loss that dropped the Eagles to 3-6 last year.

This year, Reid’s contract year, those collapses weren’t going to be tolerated.

The Eagles are giving up 20.8 points a game, which is ranked 13th in the NFL, allowing teams 330.8 yards a game, which is 12th in the league. A glaring weakness has been the Eagles’ inability to get to the quarterback, with a mere seven sacks, which rates near the bottom of the NFL, at 30th.

Against Detroit, Lions’ quarterback Matt Stafford tore the Eagles up with 17 fourth-quarter points. He was 13-for-22 in the fourth quarter for 187 yards, scoring once and throwing for another score.

The Eagles went to a different defensive scheme in the fourth quarter, going against what they had been doing the first three quarters, and that was relying on the front four to pressure Stafford.

Lions’ receiver Calvin Johnson had one catch for 28 yards through the first three quarters, but in the fourth quarter and overtime alone, on one-on-one coverage, he had five catches for 107 yards in the fourth quarter and overtime.

That’s what led to Castillo’s firing. The smoking gun was provided by Nnamdi Asomugha.

“I can’t explain what happened in the last five minutes,” said a very dejected Asomugha after the Lions’ game. “It was the moment where we needed to step up and make a play, and they were the ones that just kept doing it. There wasn’t much that needed to be said after the game. It was embarrassing that we lost the way we did, and that the fight wasn’t there at the end of the game like it had been all year pretty much.”

Asked if the Lions did anything different in the fourth quarter, Asomugha said, “Not really. I think we did some different things. We blitzed a lot more in the fourth quarter. We moved guys around a bit more. They kept it the same. In the fourth quarter, we did a lot of blitzing, They were able to find the matchups they wanted.”

This had been coming. Someone had to be blamed for the Eagles 3-3 stumble.

As for Bowles, he has the respect of the locker room. Bowles has NFL experience and served as interim head coach of the Miami Dolphins. Bowles was the defensive coordinator in waiting. The Dolphins finished strong late last year under Bowles.

Reid tried to hire Bowles in 2011. He knows how to call a defense. He coached under Bill Parcells in Dallas and defensive line coach Jim Washburn and Bowles have a good working relationship.

Joseph Santoliquito is a contributing sports blogger for CBS Philly.

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