The 47-year-old took golf's conservative fashion genre to another level with a long-sleeve collared office shirt at Sawgrass, and his struggling 79 was sympomatic of a wider malaise among the much-hyped marquee groups at Sawgrass.
Earlier in the week Mickelson mockingly called out Tiger Woods
for a big-money match, but the value of the stakes might have dropped after his playing partner opened with a lackluster level-par 72 at the prestigious Ponte Vedra Beach tournament .
Despite dropping seven shots in his last five holes as his energy levels dropped, five-time major champion Mickelson was happy to discuss his day's look.
"I think nobody does kind of slightly overweight middle-aged guy better than me, and this says exactly who I am," said Mickelson, who also wore his new sponsor's gear in a practice round at the Masters.
"It says that if you can play golf at the highest level, imagine how comfortable it is in the office."
The third member of the former champions trio Rickie Fowler could only shoot 74, while another big-name triumvirate to misfire was that of Rory McIlroy (71), Jordan Spieth (75) and Justin Thomas (73).
Instead, current world No.1 Dustin Johnson joined a six-way tie for the lead at six under after a sparkling round of 66 over the Stadium Course.
The big-hitting 33-year-old, who last won in January, was tied with fellow Americans Webb Simpson, Chesson Hadley, Matt Kuchar, Patrick Cantlay and Sweden's Alex Noren.
It was the first time old rivals Mickelson and Woods, 42, had been paired together since the first two rounds of the 2014 US PGA, and expectations were high that the two resurgent veterans -- Mickelson won earlier this season, and Woods has made a promising return from back fusion surgery -- could treat fans to an electric golfing duel.
But former world No.1 Woods, still easing his way back into competitive golf, said: "No, what my playing partners are doing, there's too many guys out there that are playing really well and going low, and my responsibility was to go low and shoot something in the red [under par] today."
He may not have done that, but Woods was still able to unleash a monster 349-yard drive on the par-five ninth as he bettered Mickelson like he did so many times in their heyday.
Mickelson will attempt to become only the sixth player to clinch golf's grand slam of all four major titles at next month's US Open at Shinnecock Hills, NY.
The popular left-hander, who joined Woods and other members of the prospective US Ryder Cup team at captain Jim Furyk's Ponte Vedra Beach home earlier this week, holds a record six runner-up spots in the year's second major.
The infamous island-green 17th hole
at TPC Sawgrass claimed 24 balls in the water in round one, including Mickelson's.
The winner of the Players Championship, unofficially dubbed the "fifth major," will pocket a tournament-record $1.98 million from a record purse of $11 million.