Rory McIlroy handing over his scorecardÂ on his ninth hole, the par-5 18th, of the Honda Classic on Friday.  PALM BEACH GARDENS, Fla. — Applause drowned out the pulsating music Tuesday night as Rory McIlroy made his way to the X taped to the carpet in the resort ballroom. McIlroy, wearing jeans, a dress shirt and pointy-toed shoes, had just been introduced as the first global brand ambassador for Bose, an audio equipment company.  It was a timely merger of man and machine. If anybody needed noise-canceling headphones to tune out the world, it was McIlroy, whose slow start in 2013 has generated criticism on both sides of the Atlantic.  On Friday he set more tongues lashing by abruptly withdrawing from the Honda Classic after completing eight holes of his second round. It was the first time in 55 starts as a professional on the PGA Tour that he withdrew during a tournament.  McIlroy returned this week to PGA National Resort and Spa seeking to become the 41-year-old tournament’s only back-to-back champion besides Jack Nicklaus. Instead, the event led to his latest disappointment since he made the highly lucrative but risky move of changing his equipment from Titleist to Nike at the beginning of the year.  The early returns have not been promising: he missed the cut in Abu Dhabi in his season debut, switching to his old putter in the second round, and lost in the first round last week in a World Golf Championships match-play event outside Tucson.  The week of his title defense began with McIlroy brushing off criticism in the news media in the United States and the United Kingdom over his equipment change. “It’s not like I’m pushing for answers or I’m looking for answers,” he said. “Everything’s there. It’s just a matter of putting it all together.”  Asked if reporters were making too much of it, he laughed and said: “Of course. Like yous always do with everything.”  McIlroy was not laughing Friday when he walked off the course after depositing his second shot on his ninth hole, the par-5 18th, into the water. It was his third wet ball of the day, and he stood at seven over after eight holes.  He left the grounds without offering an explanation, the first indication that the intense scrutiny that goes hand-in-hand with being golf’s global brand ambassador is darkening McIlroy’s sunny disposition.  Ernie Els and Mark Wilson, who were paired with McIlroy, were unaware of any physical distress that would have prompted him to retire from the tournament. McIlroy gave no hint of a problem before his round, posting on his Twitter account Thursday night a photograph of a birthday dinner for his mother, Rosie.  An hour after his withdrawal, in a statement released by his managers, McIlroy said he was bothered by a sore wisdom tooth that did not respond to a pain reliever.  “It was very painful again this morning, and I was simply unable to concentrate,” he said.  McIlroy added, “This is one of my favorite tournaments of the year and I regret having to make the decision to withdraw, but it was one I had to make.”  There is no manual for the care and maintenance of a global brand, as evidenced by the awkward handling of McIlroy’s withdrawal. Since ascending to No. 1 with his win here last year, McIlroy has tailored his tournament schedule to give himself time to recharge; hired Michael Bannon, his longtime coach and a club pro, to work with him full time; and relocated to Palm Beach County, Fla., where the sun shines brightly but the spotlight is not quite as hot.  McIlroy, who bought a multimillion-dollar home in a gated community five miles from PGA National Resort and Spa, said the local populace largely left him alone.  “Palm Beach is a bit like that,” he said. “Everyone is wealthy in their own right, and they think they’re important, and they’re caught up in what they’re doing.”  McIlroy’s Nike deal is worth tens of millions of dollars, but nobody who has spent time around him believes that was his motivating factor in making the switch.  “I truly believe he didn’t leave Titleist for any money reasons,” Wilson said. “He just wants to be with a company that represents some of the best athletes in a lot of sports.”  The job of handling a golfer aligned with the best athletes on the planet falls mainly to Conor Ridge and Colin Morrissey, who founded Horizon Sports Management, the Dublin-based company that has represented McIlroy since 2011. To lessen his learning curve, Ridge said, he sought out people who had guided the careers of some of the world’s most popular entertainers and sportsmen. Among them was a fellow Dubliner, Paul McGuinness, the longtime manager of U2, who told him, essentially, to never forget that performance is the engine that should drive any marketing campaign.
Top-ranked Rory McIlroy walked off the course midway through the second round, his third poor showing since switching to Nike clubs.