If social media is any kind of gauge, the reactions to the button-down dress shirt Phil Mickelson is wearing at the Players Championship are … well, here are a few snippets from the incredulous Twitter mob:
“Ridiculous.”
“Uncomfortable.”
“Looks like he should be doing my taxes.”
One quick-wit superimposed a photocopier onto a picture of Mickelson with the caption: “Mickelson has found himself in some serious trouble with an error #2734 paper jam.” Another observer theorized that Mickelson’s sloppy, seven-over 79 in the first round was “a direct result of that shirt he’s wearing.”
They say any publicity is good publicity but surely not this kind of publicity, right?
“I would say au contraire,” Kevin Lavelle said from his Dallas office Friday morning. Lavelle is the founder and CEO of Mizzen+Main, a six-year-old apparel company that manufacturers the stretchy performance-fabric shirts that Mickelson is modeling this week in Ponte Vedra Beach, Fla. “Everyone in the sports world is buzzing about it.” 
That’s what happens when one of the world’s most recognizable athletes turns golf style on its head with an outfit better suited for a comptroller.
“We had our best sales of the year yesterday,” Lavelle said. “It was the most engaged, mentioned and trafficked day in company history.” He declined to say exactly how many of the $125 shirts his company sold but that it was “a meaningful multiple over a normal day.”
Lavelle said Mizzen+Main counts more than 600 professional athletes among its customers, including Houston Texans defensive end J.J. Watt, who is a spokesperson, but Mickelson is breaking new ground for the company. He and Lavelle inked a partnership earlier this year that gave Mickelson a significant ownership stake in the company. When Mickelson debuted his new look in a practice round with Tiger Woods at the Masters last month, “he knew exactly what he was doing,” Lavelle said. “That created an enormous amount of buzz.”
Under the terms of the deal, Mickelson is not required to wear the shirts, Lavelle said, but with an equity interest naturally it benefits him to do so. More eyeballs mean more sales. Some of the Mizzen+Main folks debated whether a steamy spring round in Florida was the best place for Mickelson to model the shirt — “we were worried it was going to look like he’d jumped out of a pool,” Lavelle said — but Mickelson insisted the timing was right.
“He played 18 holes of golf walking in Florida in May and the shirt looked perfect,” Lavelle said. 
Despite Mickelson’s marketing clout, it’s hard to imagine dress shirts sweeping the golf world by storm. But that was never the point, Lavelle said. His hope is that when consumers see that the shirt is comfortable and flexible enough to play golf in — it’s 85% polyester and 15% spandex — they’ll be confident that it will also hold up when they’re grinding out spreadsheets or expense reports.
During the R&D phase for the shirt, Lavelle said he drew looks from his neighbors when he went jogging in a prototype of the button-down with his pair of Rhodesian Ridgebacks at his side.
Lavelle knows what he has in Mickelson: one of golf’s most loyal endorsers. When Mickelson met the press Thursday evening, still smarting from his 79, he gamely transformed from pro golfer to pitchman.
“I think nobody does kind of slightly overweight middle aged guy better than me, and this [shirt] says exactly who I am,” he said to a scrum of reporters. “I’m really happy with it. I think you shouldn’t knock Mizzen+Main until you try Mizzen+Main.”
