Tennis has been drifting inexorably towards a crossroads for at least five years, and rarely has that been more clearly underlined than in events 700 miles apart this weekend. In Milan, the conclusion of the inaugural Next Gen tournament, packed with innovations such as the shot clock and shortened points, celebrated the arrival of the best of the young prospects in the game, while in London those left standing among the established elite dragged their tired bones to the white line for their final showdown of the season.

There is a decent chance there will be a couple of memorable collisions in either of the two four-player groups at the O 2 Arena, with the preferred climax a decider next Sunday between the world No1, Rafael Nadal, and his nemesis on this surface, the ageless Roger Federer. Certainly, there will be more actual court time in London than there has been in Milan – but is this what fans still want?

It is a debate that is growing in volume before a meeting of the grand slam committees in London next week. They will quietly mull over the possibility of reducing their fields from 32 seeds to 16, although the likelihood of in-match coaching is remote, and we are unlikely to see a shot clock at Wimbledon for a few years yet. Tennis, like golf, does not shout.

Nevertheless, tennis, as popular as it is worldwide, is vigilant in its pursuit of TV and turnstile revenue in an era of unprecedented excellence, and Chris Kermode, the forward-thinking executive chairman of the ATP, asked rhetorically: “In another 10 years, is anybody coming to watch a six-hour product? I doubt it. I really doubt it.”

The players are wondering too, but with less enthusiasm for change. The shot clock is popular with many younger players, given that it urges the older slow-coaches they suspect of gamesmanship to get on with it. But the more fundamental move would be cutting seeds in the grand slams to 16. As it stands, numbers one to eight can play only numbers 25 to 32 in the third round, which more gently eases them into the fortnight.

As Federer, the game’s elder statesman, observed, this gives the higher seeds an obvious advantage – and one which he is prepared to sacrifice. Asked if he thought it would be introduced in his remaining time in the game, the 36-year-old said: “That’s how it used to be when I came up, way back when. There’s definitely something intriguing about having 16 seeds. I do see the problem of the 32 seeds, plus you have eight seeds who get byes at Masters 1000 [events].

“You have these stairs that can make you feel safe and I feel like there’s too many to get to the top. It’s hard to drop out and it’s hard to get into. Having 16 seeds? That might be interesting. The draw could be more volatile, [with] better matches in the first week.

“The top guys have made a habit of not cruising but getting through the first week quite comfortably for a long period of time. Playing against the Nos17, 19 or 20 in the world is not something I really want to do, but it is what it is.”

Federer kept a close eye on developments in Milan, where the 21-year-old South Korean Chung Hyeon beat Russia’s Andrey Rublev to win the inaugural title in just under two hours. Federer was intrigued, although not totally convinced. “I enjoyed watching it on TV, I watched a lot of matches,” he said. “Sure, there were a lot rule changes but it didn’t feel too different to overall.”

However, he is protective of his personal strengths and realises shorter sets would not suit his expansive game, where innovation and the ability to come back from intermittent dips help him to prevail over lesser opponents. “The longer sets allow you to stretch a lead, [to feel] more comfortable at times, try different things,” he said. “You can work on stuff – whereas, when every point counts so much, there’s no room for anything any more. There are positives and negatives to it but, for the most part, I don’t like to see anything change that much, to be honest.”

The ever-grinding Nadal is unsure, either way. “I don’t know if that’s the way or not,” he said of the Milan experiments. “But by trying new things you can find a better way. If we don’t try anything, you cannot say that works better or that works worse. There’s a couple of things that I like, a couple of things that I don’t like. Nothing is perfect.”

And that is a definitive judgment on tennis, and sport generally. There never has been a perfect tennis match, and, despite the sublime skills of these players, there never will be. They might come close this week, but inevitably they will fall short. Yet this weekend definitely has the feel of tennis reaching another crossroads. There have not been many. As Nadal said on Friday: “The net was the same height 50 years ago.” But we have seen tie-breaks and championship points over the years, as well as a general urgency to quicken play.

Crossroads, popularised by Eric Clapton, was written in 1936 by Robert Johnson, a blues standard which has been mythologised as the pained selling of his soul to the devil in exchange for his talent. Tennis is not quite selling its soul. But parts of it already wear a price tag.