Tennis is one of the few sports that does not allow players to interact with their coaches during play. However, the US Open will experiment with it during its qualifying rounds this year.
Coaches will be able to speak or gesture to their players from their seats as long as they're on the same end of the court and do not disrupt the play.
Djokovic supports the idea but would prefer the introduction of headsets in tennis so that players could communicate with their coaches wirelessly, which is something the Association of Tennis Professionals (ATP) is reportedly planning to trial.
"I think that's a cool idea, to be honest," he said, as quoted on Tennis.com. "Signalising different symbols is a little bit—I have to think about that.
"But when you have your player on your side, it's fine. Of course, when it's within that time limit, respect towards the other player, the rhythm of the server.
"The headset, also, I think is fine. This is kind of an intimate conversation where you feel comfortable, that you communicate wirelessly with your coach who is there.
"I think it is also a good idea for the commercial part. Obviously there's a lot of headset companies that would probably include their budget into tennis, which is always great," he added.
"But I don't know. They've said that the TV audience possibly could hear what you were speaking with your player. Still have to be a bit careful."
The Serbian ace also questioned why it has taken tennis so long to introduce interactions between players and coaches, citing it as one of the few global sports that do not utilise such a common occurrence.
"When the WTA introduced on-court coaching, many ATP players were not really positive about it," he added. "I thought it was a good move for the sport."
"I mean, we're probably one of the only, maybe [the] only global sport that doesn't use coaching during the play. Even golf, individual sport, you have caddies that you communicate with throughout the entire course."
However, Federer is not entirely in support of on-court coaching as he does not think it will be beneficial for all the players.
"I'm not all for it," he stated. "I find it kind of cool that in tennis, you know, you're sort of on your own out there. Not everybody has the same amount of resources for coaching, as well. So I'm not sure if it's that beneficial.
"But, you know, might be interesting for some people to see. I know that some parts of the world, coaching at junior level and all that stuff is totally normal, that the coaches and the players speak," Federer said.
"I'm sure it's not going to make that much of a difference because I'm sure there's hand signs going on as we speak... It doesn't take much to understand that message. I'm not really for it."
Another new rule that the US Open plans on trialling is the introduction of a shot-clock that will restrict the time between points to 25 seconds. By forcing a player to serve within 25 seconds of the last point, it allows for less time wasting and a faster-paced game which Federer finds interesting.
"The shot-clock is an interesting one. But how do you judge, you know—when you finish after a drop shot, it's been a tough rally, the guy has to run back to the baseline," he explained. "Sometimes we need to have some leeway.
"But I do believe we should enforce the rule at some stage, somehow, because maybe too many players have gone over the limit. That's where we are now. I'm not sure if it's good, but give it a try, I guess."
The US Open will take place from 28 August to 10 September.