JUAN CASTILLO did not report for work at 4 a.m. Tuesday.

Less than 5 months ago, Castillo said he would "take a bullet" for Andy Reid, and Monday night he did.

Reid's promised all-encompassing bye-week review barely got started before the Eagles' coach decided to make a huge change, firing Castillo as his defensive coordinator after 22 games, with the team 3-3 this season and the Eagles' defense ranked 12th in the NFL. Secondary coach Todd Bowles, widely viewed as coordinator-in-waiting when he came aboard last January, was given the job, though Reid insisted that was not his plan all along.

"I would like to thank Andy and Mr. [Eagles chairman Jeffrey] Lurie for the opportunity that they gave me," Castillo said in a text message to the Daily News. "And thank my players for playing harder than anybody else in the NFL."

Castillo told Comcast SportsNet's Derrick Gunn he didn't see himself as a scapegoat: "The thing that hurts is that I let down coach Reid, I let down the organization, I let down the city . . . I didn't get it done."

Reid was vehement that he alone made the decision, that saving his own skin was not part of his thought process, and that whether reporters, fans and even players might detect a whiff of panic from such a precipitous move was beside the point. (Lurie has said the Eagles need to do better than last year's 8-8 for Reid to keep his job.)

Reid hinted that more moves might be pending; asked about turnover-plagued quarterback Michael Vick, Reid gave the same "as I sit here today" endorsement he'd given Castillo the day before.

"I'm going through and evaluating our football team, both coaches and players. So, this is one of the moves, and we'll see where this goes from here," Reid said.

Reid said there was no one stat or circumstance that drove the decision, unprecedented in his 14-year Eagles tenure. He acknowledged that fourth-quarter problems last season and the last 2 weeks played a role. Certainly, observers have inferred that Castillo was unable to counter the adjustments of experienced offensive coordinators.

"I think the world of him. I feel full responsibility for putting him in this position," Reid said. Later, he added that he'd spoken with Castillo Monday night and Tuesday morning.

Reid said in speaking with Castillo he was "as real as I could be, to a good friend. He understands the business. Thank goodness he understands it. He knows that he's going to be all right. This isn't the end of his road or anything."

Castillo, 53, spent 13 seasons as the Eagles' well-regarded offensive line coach before Reid stunned the football world by naming him defensive coordinator in February 2011. The rationale was that Castillo knew a lot about defenses from devising protections against them, that he had been a linebacker in college and in the USFL, and that he used to talk strategy with the Eagles' esteemed d-coordinator Jim Johnson, who died in 2009.

It seemed an extraordinary gamble to most observers at the time and it made even less sense when the lockout-challenged Eagles blew five fourth-quarter leads into losses in 2011. Had Reid fired or reassigned Castillo after the 2011 season, no one would have been surprised. In fact, Reid tried to hire former Rams head coach (and Eagles assistant under Johnson) Steve Spagnuolo for some sort of role Reid said then would not have involved replacing Castillo, exactly, but Spagnuolo decided to take over the New Orleans defense instead.

"I thought we made progress" toward the end of last season, Reid said Tuesday, when asked why he was doing this now and not last January. "I thought we kind of did that through training camp, through the first couple games, and then there were just some things that I go, 'I've got to look at this.' That's kind of where I went."

Reid said he "started seeing some trends come back that I wasn't real happy about."

Castillo, hired by Ray Rhodes as an offensive assistant in 1995, famously drove from Philadelphia to Green Bay as Reid was being hired from the Packers to coach the Eagles in 1999, to plead his case for remaining on the staff. He was known for his work ethic, honesty and passion, but after he took over the defense, when questions arose that required something beyond diligence, it wasn't clear what Castillo brought to the table. In the same May media session in which he declared his willingness to take a bullet for Reid, because Reid had decided to stick with him, Castillo was asked what he'd learned from the struggles of his first year.

"I learned that if you work hard, and you believe in what you're doing, everything will work out," Castillo said, to a reporter who had been hoping for something a little more insightful about the difference between coaching offense and coaching defense, in-game adjustments, scheme complexity, and so forth.

Reid called Castillo "a tremendous football coach." He said he didn't think offering Castillo an alternate position within the organization would have been fair to Castillo.

Former Eagles center Jamaal Jackson said he spoke with Castillo Tuesday, and that Castillo sounded upbeat and positive about looking for another job. Jackson, an Eagle from 2003 until this past offseason, said "it took a lot for Big Red to have that conversation" with Castillo, his loyal ally and friend. Jackson said replacing a coordinator in the middle of a season "doesn't sound like an Andy Reid move."

Defensive tackle Cullen Jenkins told 94 WIP hosts Michael Barkann and Ike Reese he could only speak for the defensive line, but "I thought we were all on board" with Castillo.

"Everybody can try to put it on the coach, or say the coach isn't doing this or that, but the coach isn't on the field missing assignments," Jenkins said. "The coach isn't on the field missing tackles, not making the plays. It all comes down to the players and it comes down to the fact that we all need to step up."

Tight end Brent Celek said: "That's what happens in this league. You gotta produce . . . I wish him luck. I've got a lot of respect for him, but if I don't do my job, they're going to be looking for somebody to replace me.

"Andy realizes the type of team we have and the potential that we have. Obviously, we as a team aren't living up to it."

Reid answered a lot of questions about how a team whose offense is 31st in the NFL in scoring, with 17 turnovers in six games, ends up trying to fix things by firing the defensive coordinator.

"Please understand that offense, defense and special teams right now, we need to get better . . . I'm just bringing this to you because this is what's happened so far," Reid said.

Reid said he didn't consult any players. He said he did talk to corner Nnamdi Asomugha about Asomugha's comments following the Detroit game, when Asomugha expressed displeasure over strategy changes down the stretch, after the Birds shut down the Lions through three quarters. Reid indicated Asomugha told him he did not mean to criticize strategy.

"I'm not going to get into specifics," Reid said when asked what bothered him about the defense. "It was how I felt at this particular time, the things that I think we need to go forward doing . . . This was my decision and my feel and so on, so I've got to trust my instincts on it, as hard as it is."