While Federer cautions comeback success can be a "slow process", he believes all three former champions will eventually return to Top 10 form.
"Yeah, so I expect obviously from the likes who have been extremely high up in the rankings, who have won slams, like Stan, Andy and Novak, of course I expect greatness from them. But I wouldn't be surprised if it worked out for them as well like it worked out for me-and Rafa".
At Andy Murray Live on November 7 the player took on Roger Federer in a singles match before he was joined by his brother, Jamie, against the retired players Tim Henman and Mansour Bahrami in the doubles.
"He's been working very hard in his rehab and his practice", Delgado told Sky Sports.
"It was great to be back and see all the guys again and also to give him the feel of coming to a tennis event". We are very confident and hopeful that he will be back to his best.' 'He played the exhibition last week in Scotland with Federer, that was good.
That was the first time [since losing to Querrey in the quarter-finals at Wimbledon four months ago] that he had played against anyone at that level. That was a progression as well.
Murray, Wawrinka and Djokovic are not alone in making their returns to the sport, in what's been an injury-hit year at the top-end of the ATP Tour. When asked if Murray would choose not to practise in the middle of the tournament, Delgado said no and suggested Federer could be carrying a knock.
"I hope also Kei, Thomas and Milos all find their way back on tour and prefer to be in Australia because that would make it quite epic, comeback for all the guys", Federer said.
'They are sort of weaving their way in. I didn't choose to take the time off a year ago. You have the young guys coming through.