PHILADELPHIA — Juan Castillo’s offense-to-defense coaching experiment backfired in Philadelphia, costing the defensive coordinator his job.

Castillo was fired by Eagles coach Andy Reid on Tuesday and replaced by secondary coach Todd Bowles. It was the first time Reid dismissed a coach midseason in his 14 years in charge.

“I put Juan in this situation and things didn’t work out the way I had hoped,” Reid said. “I take full responsibility for putting him in that situation.”

The move came two days after the defense blew a 10-point lead with 5:18 remaining and lost 26-23 in overtime to Detroit. A week earlier, the defense allowed Pittsburgh to rally for a winning field goal in the final seconds.