Ivan Ljubicic, who never played in a Grand Slam final, will replace Edberg as 34-year-old Federer's co-coach (with Severin Luthi) in 2016. Former ATP journeyman Jesse Levin, who had a career-high ranking of No. 69, will mentor the 20-year-old Keys.
Is the "supercoach" an endangered species?
Neither Federer nor Keys managed to win a major title while working with their most recent supercoach. Nor has Michael Chang's protégé, Kei Nishikori. And who can forget Jimmy Connors one-match disaster as Maria Sharapova's coach, or that Martina Navratilova lasted just a few weeks as Agnieszka Radwanska's mentor early this year?
It makes you wonder. Has the much-hyped trend of elite players striking up partnerships with celebrated former champions run its course?
In fact, has it even been as successful as we expected?
Let's review. Connors and Andy Roddick set up an unexpected and novel partnership in 2006 and enjoyed a fruitful 19-month relationship. But Roddick never did win that elusive second major under Connors' guidance. It seemed just a one-off pairing, but the "supercoach" theme re-emerged and caught fire when Ivan Lendl took charge of Andy Murray's career in December 2013.
The idea was compelling at first largely because of the human-interest angle. Both men had been dominated by their tennis-focused mothers. Could tough-guy Lendl, once a perennial Grand Slam bridesmaid just like Murray, transform mopey Andy into a champion?
The relationship lasted for two years, during which Murray punched through to win his first major (on his fifth try with Lendl) at the 2012 US Open and went on to win the Olympic gold just a month later. In 2013, Murray became the first British man to win Wimbledon in 75 years. Lendl and Murray split in March of 2014, and Murray hasn't won a major since.
Lendl and Murray did more than just establish the supercoach trend. They set a bar that only one other partnership has come even close to approaching. Boris Becker was brought on as top-ranked Novak Djokovic's co-coach in 2014. Becker was assigned the job of helping Djokovic navigate the most critical moments of his most crucial matches because his record in Grand Slam finals in 2012-13 was 2-4.
Since then, with Becker in his guest box, Djokovic is 4-2 in major finals. The first of the two losses was at the French Open of 2014, when Nadal was still at his "King of Clay" peak. The other loss was at this year's French Open, on a day when there was nothing Djokovic -- or anyone else -- could have done to stop Stan Wawrinka.
After that, the drop-off in the success of supercoaches is abrupt. Loosey-Goosey Goran Ivanisevic did a terrific job of helping Marin Cilic overcome his tendency to get mired in analysis paralysis. But such makeovers are almost always temporary, like hypnosis. Cilic won the 2014 US Open, and that was a priceless contribution from Ivanisevic. But since then, Cilic has reverted to his former self. He's had some injury troubles, too. But once again, he's a big, quiet, dangerous but inconsistent guy.
Nishikori, runner-up to Cilic in that unusual 2014 US Open final, has a similar story. He added Chang to his coaching team in 2014 under the theory that some of Chang's storied grit and consistency would rub off. Some of it certainly did: Nishikori went from a top-20 player to one just outside the elite circle of Grand Slam champions. But Nishikori was a disappointment in majors this season, going just 9-4 and never reaching higher than his quarterfinal appearances at the Australian and French Opens.
It's always been difficult to figure out Federer's relationship with his coaches, because astute Federer may be his own best coach. Thus a "supercoach" like Edberg seems more like a sounding board or adviser.
The partnership undoubtedly brought an extra touch of class to the center courts of the world, as well as a greater emphasis on attacking tennis. But then, Paul Annacone (Federer's former coach) had advocated for a more aggressive game as well. In the end, though, Edberg was part of the team for 24 months during which Federer's main mission -- winning a major -- remained unfulfilled.
The latest split, between Keys and Davenport, is notable. The young player chose to cut loose a three-time Grand Slam champion and former No. 1 -- even after Keys moved up to No. 18 in the rankings, 13 spots higher than she was in 2014.
Keys claimed her decision was based on the fact that Davenport, a mother of four and a television commentator, was unable to travel as much as Keys wanted. "It wasn't like we had some big blowout fight and we hate each other," Keys told a WTA publicist. "That's not the case. Obviously, we want to still work with each other. She just has so much."
Still, Davenport had "so much" this year, too, and things worked out pretty well. Perhaps Keys is just trying to back away from the pressure of high expectations, which are also a byproduct of hiring a supercoach. The antidote, for Keys: Hire Levine, a journeyman.
Is this the start of a trend?