FOXBORO — Bill O’Brien is mortified.

When the New England Patriots receivers coach hears some of the stories that Brown coach Phil Estes shared from their days together on College Hill, O’Brien can’t believe it.

“Oh Phil, Phil!,” O’Brien exclaims when a few of Estes’ tales are retold, shaking his head as he realizes that his old friend has revealed some doozies.

Like the time when Estes was trying to get O’Brien’s attention when the young Bears assistant was on the phone with another coach. When O’Brien wouldn’t acknowledge him, so Estes took a pair of scissors and cut the phone cord. O’Brien, his eyes wide, tried frantically to twist the frayed wires back together, saying into the receiver, “Hello? Coach?”

Or O’Brien’s penchant for doing spot-on impressions of those he knows — voices, mannerisms, the whole deal.

Or the late night in Providence that involves the East Side bus tunnel. But O’Brien pleads that that one remain secret.

But Estes’ recollections paint a picture of a young man who knew how to have fun even as he charted a path for his coaching career that would take him to some of the top college programs in the country and now to the NFL’s most successful franchise this decade.

“When I came in (to the Brown program) with Mark Whipple, Billy was a holdover of the previous staff,” Estes recalled. “He knew the lay of the land, he had played here. He had one of those great personalities; it was very easy to bond with him.”

A native of Andover, Mass., O’Brien arrived at Brown in 1988, following in the footsteps of his father and older brother, both of whom played for the Bears. Having gotten the bug for college coaching, the former linebacker/defensive end stuck around as a grad assistant for two years before moving to a similar position at Georgia Tech.

By that time, Estes had taken over at Brown, and offered O’Brien his first paying assistant’s gig as running backs coach and recruiting coordinator. But it didn’t last long.

“He came to me three weeks later and told me, ’Phil, I had to do this and I can’t believe it’s happening, but George O’Leary has offered me a full-time job at Georgia Tech,’” Estes said. “He was leaving me in a bind it was during recruiting, but it was the best decision.”

In three years, O’Brien became Tech’s offensive coordinator, and followed O’Leary to Notre Dame only that didn’t last long, either. When it was discovered that O’Leary had fudged some lines on his resumé, he was forced to resign just days after being named head coach.

Fortunately for O’Brien, new Tech coach Chan Gailey welcomed him back, as offensive coordinator and assistant head coach. Then it was two years at Maryland and two more at Duke before O’Brien got an offer from an e-mail buddy.

Bill Belichick.

“In 2001, when I was at Georgia Tech, we made contact through a mutual friend and just talked football,” O’Brien said. “After that I just kept in touch with him, maybe once or twice a year, send him an e-mail if I had a football question, and he would respond.”

Belichick would occasionally ask O’Brien about certain players in the ACC, to get his opinion on whether or not he thought they’d make good pro players.

“I definitely wanted to coach in the NFL at some point and I was always intrigued, watching the Patriots and how they did things, football-wise and Xs and Os wise, and how coach Belichick ran the team,” O’Brien said. “I always wanted to be a part of that, so when the opportunity arose it was something I didn’t give a second thought to. I just definitely wanted to be a part of it and learn from what I consider the best coaching staff, the best players in the league.”

O’Brien took a pay cut to come to New England last year, as a coaching assistant. But the move was a good one all around. He says he’s learned more about football in the last 18 months than he had in the previous 16 years, and he gets to be near family and friends again.

His parents live on Cape Cod now, he has a brother in Lexington, Mass., and his in-laws are a few hours away in New York.

The support system comes in handy: Bill and Colleen O’Brien’s older son, 6-year-old Jack, was born with lissencephaly, a rare brain malformation. The disease has left him developmentally challenged; currently, he cannot feed himself or speak, but doctors have never put a ceiling on what he might be able to do someday. The couple also has a 3-year old, Michael.

Charged with preparing the Pats’ wideouts, Estes said he wouldn’t be surprised if O’Brien moves up the ranks in the NFL as he did in the college ranks.

“Absolutely. Absolutely,” said Estes. “He’s very organized, very perceptive, I think he sees things on the field that others may not see. He gets along very, very well with other coaches, but at the same time he’s very demanding. It’s only a matter of time.

“People that really know him know that he’s something special.”

smanza@projo.com