An unmistakable figure sat with Roger Federer’s entourage at the US Open last week: Michael Jordan.

His Airness is no tennis aficionado—this was apparently his first-ever appearance at the tournament—but like the rest of the Arthur Ashe stadium, he was there to look at Federer’s footwork. The 17-time Grand Slam winner was wearing new Nike tennis shoes that he designed himself, which are based on the Air Jordan basketball shoes that Nike has produced with Jordan for 25 years.

Federer’s shoes, officially known as Zoom Vapor 9 Tour AJ3s, are another example of Nike’s supreme skill in managing what it calls “demand creation.” Federer and Jordan are not believed to be friends, but Nike still released a short video of them messing around on the piano like old chums:

And Federer was corralled into joining Instagram to post a shot of the two of them:

Why has Jordan been drafted in to give Federer’s shoes a lift?

Because, even a decade after he retired, Jordan remains one of the biggest draws in sport. He is still paid around $90 million a year by Nike, who in turn made $2.3 billion on Jordan-associated merchandise in 2013. These figures dwarf those of any of Jordan’s successors in the NBA. At the US Open, Federer’s bewildered opponent, Marinko Matosevic, called out to Jordan when he spotted him; the court cameras put him up on the big screen, and the commentary team were frequently distracted. The coverage also meant that a limited run of the trainer, which retails at $200, sold in just minutes. Nike is sure to produce a second run, but one that is small enough to maintain a scarcity value.

But the real point of the collaboration is the hint it gives about what might come next for Federer. Even with his remarkable stamina and fitness—he has played in every Grand Slam tournament for the past 15 years—he is 33, a pensionable age in men’s tennis. For his sponsors, the biggest of which is Nike, it is time to plan what comes next.

Federer is the most recognizable player on the planet. Statistically, he is also the best ever, and he wins his matches with style. These credentials, when combined with his squeaky clean reputation, make him a big draw for sponsors. He has long expressed an interest, perhaps stoked by his sponsors, in how he looks on court. At Wimbledon 2009, he strode out wearing a military-style jacket and a waistcoat, and carrying a gold-trimmed bag emblazoned with the Nike swoosh and his own RF logo. The reaction was equal parts respect at his chutzpah and dismay—at this, the most British of events—at such peacocking. It is not a look that has aged especially well, but it marked his first leap into designing.

It now seems likely we are going to see a lot more of that RF logo. With the Jordan brand shoring up Nike’s dominant position in basketball, Nike is looking elsewhere for growth. Tennis is a logical area to expand, as it has a readymade frontman in Federer. It also opens a new demographic for the company: tennis is by no means a youth-driven sport. There is plenty of opportunity for tennis fans in their 20s and 30s, who grew up watching Federer win slam after slam, to wear future Nike-RF shoes on court for the next 30 years. There is also a precedent for tennis shoes as design classics. Adidas’ Stan Smiths are four decades old and are still being manufactured. This is important, as sneakerheads are as important to Nike as amateur basketball players when it comes to buying Air Jordans.

At some point in the next two years, Federer will announce his retirement from tennis. It will be a watershed moment for the sport. It will be the end of Federer the player, but it might just be the beginning for Federer the brand.