Two-time Pro Bowl quarterback and Super Bowl champion Brad Johnson discusses the impact Gruden will have on the Oakland Raiders’ locker room and on quarterback Derek Carr.

ALAMEDA, Calif. — Jon Gruden looked genuinely perplexed.

At a news conference here Tuesday, he was asked to describe the process by which he decided to give up his gig as an analyst for Monday Night Football and take over as head coach of the Oakland Raiders — nine years after he last coached in the NFL and 16 years since he coached the Raiders.

“It’s a mysterious way that it all came together,’’ he said at the Raiders’ training facility.

But Raiders owner Mark Davis, retired coach Dick Vermeil and Gruden himself helped at least partly solve the mystery.

More: Energized Gruden embraces second turn with Raiders

More: The tough questions start for Jon Gruden and Raiders

More: NFL coaching tracker: Latest news on candidates, job openings

Start with Davis, the team owner who said for each of the past six years he visited Gruden in Tampa and marveled at seeing Gruden wake up at 3 a.m. and watch game tape, often in preparation for Gruden’s job at ESPN.

“It took me six years chasing down Jon,’’ Davis said with a grin.

During the press conference, Davis thanked Jon Gruden’s mother, Kathy, “for being one of my biggest cheerleaders.’’ Turned out Davis had a strong ally in his attempt to woo back Gruden.

“I simply encouraged (Gruden) to step into the role he loved the most, that of beng a coach,’’ Kathy Gruden told USA TODAY Sports by text message. “This opportunity came and seemed to be the chance of a lifetime. A perfect fit at a perfect time.”

Noting that Gruden’s passion for breaking down game tape and football never waned over regular visits to Tampa, Davis said he told Gruden that he was “wasting his time’’ in doing anything other than coaching.

Gruden apparently heard the same thing from Vermeil, the retired NFL coach who returned to the sidelines after a 15-year absence. Vermeil said he had been encouraging Gruden to get back into coaching for the past few years and sent him at least one text message that read something along the lines of, “Get your ass back in coaching. I waited too long, don’t you do it.’’

Vermeil retired from the Philadelphia Eagles in 1982 before taking over the St. Louis Rams in…