MEXICO CITY—Last week Tim Mickelson, a nascent agent, was eating lunch with his prized client, Jon Rahm, at a cantina in Scottsdale, Ariz. Mickelson coached Rahm at Arizona State until last year, when both turned pro. As coach to a prodigious but raw talent, Mickelson often had to toe the line between hectoring the 22-year-old Rahm about playing the percentages and giving him the freedom to let his gifts flourish. This led to an inevitable question over the fish tacos: How has Mickelson's golf worldview been influenced by his older brother, Phil, a Houdini in alligator shoes? Tim chuckled and said, "Well, Phil is not a really useful model because he can do things no one else can. And on the golf course, no one tells him what to do."
On Friday, during the second round of the WGC–Mexico Championship, Tim finally got the chance. Sort of. Phil's career-long caddie, Jim (Bones) MacKay, began the day with his digestive tract in revolt. Tim, who was on-site to fuss over Rahm, was notified that he might be needed in relief, so he followed along as Phil and a clearly addled Bones began the round on Chapultepec Country Club's 10th hole. The first three holes play straight downhill and Bones, looking ever greener around the gills, managed to keep up. But the par-3 13th hole begins a long, inexorable march up the side of a mountain in very thin air. "He looked up that hill," says Phil, "and was like, I'm not gonna make it."
At that moment, Tim was enjoying an uneventful visit to a portable restroom, but he took over on the 13th green. On 14, their first full hole together between the ropes on the PGA Tour, Phil hit an errant drive and made his only bogey of the day. No doubt this made Bones feel even queasier. But both Mickelsons quickly settled into the rhythm of the round. Phil said it would have been "catastrophic" to lose Bones at a place like Augusta National, where the two have accrued so much institutional knowledge. But with Chapultepec's quirky contours and the feel shots required in high altitude, Phil had been leaning on his caddie less than usual. Tim helped calculate the yardages but otherwise, he says, "I was pretty much a bystander and carried the bag and just tried to not get in anyone's way."
Phil gave his brother more credit than that, noting that thanks to his days as a college coach he understands the nuances of competition: "Tim did a phenomenal job. He was always standing on the correct side of the tee box, always getting the divot and bringing it back while at the same time handing me my putter, he always had a ball ready if I needed a new ball." Beyond successfully completing the round, the brothers enjoyed getting to see a different side of each other. "The coolest thing," said Tim, "is that after he's been out here 24, 25 years, to see how competitive he still is. You know, ‘I want one more [birdie]. Let's get one more.' That fire is definitely still there." Phil got plenty—his three under-par 68 left him in a tie for second, two shots back of Rory McIlroy. Losing a caddie mid-round could discombobulate even the most-seasoned competitor, but Phil never missed a beat, and he credited Tim's easygoing vibe for making the day work: "We had fun out there. I enjoyed the banter, and he kept me relaxed."
Tim's calves may be a little sore, and his forehead a little sunburned—in a rookie move, he was without a hat until snagging one at the turn—but he's ready to go again on Saturday if Bones is still sidelined. It is a unique feature of Phil's relationship with his regular looper that once every season Bones is allowed to veto one of his boss's shots. Phil was asked on Friday if he would honor a veto by his little brother. "Well, yes, but it would count as Bones's for the year," he said. "I don't think Tim wants that kind of pressure."
"Trust me, I don't want Bones's job," Tim said, leaning against Phil's overstuffed bag, which weighs upwards of 30 pounds. "I have a whole new respect. Every hole seems uphill."
Phil is now in position to climb one of the tallest peaks of his career: winning again at 46, more than 31/2 years since his last victory. It's taken him two strong rounds to get him here, along with a little brotherly love.