Roger Federer
Raonic suffered a thigh injury in March and returned to the tour after a three-month gap.
Defending champion Roger Federer has withdrawn from the Dubai Duty Free Tennis Championships after undergoing knee surgery in Switzerland on Wednesday.
With Rafael Nadal absent from the tournament with a wrist injury, none of the vaunted "Big Three" will win the title on Sunday.
The 21-year-old German, ranked fourth in the world, is part of the highly-touted "NextGen" crop of 20-somethings who are making an impact on the ATP Tour.
Federer, contesting his 20th consecutive Wimbledon, is bidding to become only the second player to win nine singles titles on the London lawns after Martina Navratilova.
"It's (Hopman Cup) obviously the perfect preparation for the Australian Open and it worked so well the last couple of years, I can't wait to come back," Federer told reporters.
"It's a great comeback for me," said Federer, who was playing his first tournament after an 11-week break, having sidestepped the entire claycourt season.
Nadal returned to the top of the world rankings on Monday after winning his eighth Italian Open title to confirm again his status as the king of the clay court.
Roger Federer suffered a shock 3-6 6-3 7-6(4) defeat to Australian wildcard Thanasi Kokkinakis on Saturday
World number one Roger Federer survived a scare from unseeded Borna Coric to beat him 5-7 6-4 6-4 in the BNP Paribas Open on Saturday and set up a final showdown with Juan Martin del Potro who cruised to a 6-2 6-3 win over Milos Raonic.
Roger Federer is one win from becoming the oldest world number one in ATP Tour history after beating Philipp Kohlschreiber 7-6(8) 7-5 in Rotterdam Open
Federer survived a second set 'freeze' and an onslaught from Marin Cilic to claim a record-equalling sixth Australian Open title on Rod Laver Arena on Sunday.
Ruthless Roger Federer handed wounded Chung Hyeon an old-fashioned schooling before the overwhelmed South Korean quit with foot blisters
Roger Federer went through round-robin play at the ATP Finals undefeated for the 10th time.
Jack Sock was so certain he would not qualify for next week's ATP Finals that he had a tee time booked at Augusta National.
Roger Federer believes Andy Murray should follow his lead by ensuring he does not rush back to competitive action too quickly following the Scot's injury-ruined season.
A hoped-for fight to the finish for the year-end number one ranking at next month's ATP World Tour Finals in London will likely be a coronation for Rafa Nadal.
Roger Federer claimed an eighth Swiss Indoor title when he out-lasted Argentina's Juan Martin del Potro 6-7(5) 6-4 6-3 in front of a partisan Basel crowd on Sunday.
Top seed Roger Federer eased into the Basel Open quarter-finals with a dominant 6-1 6-3 victory over Frenchman Benoit Paire on Thursday.
Roger Federer, ranked second in the world, won the Shanghai Masters title against world number 1 Rafael Nadal on Sunday.
