New England Patriots head coach Bill Belichick, left, and offensive coordinator Josh McDaniels talk before an NFL football game against the Buffalo Bills two years ago. cDaniels has backed out of a deal to become the Indianapolis' Colts new coach, a decision that shocked the franchise hours after it announced his hiring.

BOSTON — Josh McDaniels sent ripples throughout the NFL with his decision to pull out of an agreement to become the Indianapolis Colts’ head coach.

He has yet to speak publicly about what factored into the 11th hour about-face. But McDaniels’ return as New England’s offensive coordinator keeps a possible successor for Patriots coach Bill Belichick in house.

Belichick gave no indication after the Super Bowl loss to Philadelphia on Sunday night that he plans to exit in 2018. And just last month he said that it was “absolutely” his intention to be back for his 19th season with the Patriots.

But at age 65 he’s also the second-oldest coach in the NFL, behind only Seattle’s Pete Carroll at 66.

McDaniels has been one of the hottest names in coaching searches over the past three years.

At 41, he’s considered one of the NFL’s brightest young minds. What’s more, McDaniels is someone whom Patriots quarterback Tom Brady trusts and recently called “a great coach and a great friend.”

It’s unclear how McDaniels’ decision will affect him regarding future opportunities with other NFL teams, a gamble should he never get the opportunity to lead the Patriots.

Colts general manager Chris Ballard said Wednesday that the assistants that McDaniels had already hired to be on his staff would have their contracts honored. If McDaniels ever leaves New England again, he will certainly have some repairs to make to his image around the league.

Responding to a suggestion that comfort with the Patriots might have played a role in McDaniels’ decision, former coach and current NBC football analyst Tony Dungy said in a tweet Wednesday that “there is no excuse big enough to justify this,” adding it was indefensible to leave the assistant coaches he’s hired in limbo.

Charlie Weis, who was Patriots offensive coordinator from 2000 through 2004 and coached alongside McDaniels, called McDaniels’ decision “unbelievable.”

“I know his agent, Bob LaMonte. I had his agent for 15 years,” Weis said. “And I promise you, with 100 percent conviction, this is against what Bob LaMonte wanted him to do.”