The Swiss 17-time Grand Slam champion has not played a match since July when he tumbled during the final set of a loss to Milos Raonic in the semi-finals at Wimbledon.
Federer, 35, had surgery for the first time in his career on his left knee in February and after the Wimbledon set-back he did not finish the season, missing out on the US Open and Rio Olympics.
During his time out of the game Andy Murray and Novak Djokovic fought out the world No.1 ranking and his Swiss compatriot Stan Wawrinka won the US Open.
Federer makes his return with his world ranking down to 16, his lowest since 2001.
The Swiss legend, who will partner with Belinda Bencic, said he was looking to ease his way back before the start of the Australian Open in Melbourne on January 16th.
"I'm really positive about how I'm feeling right now, and practice is going well," said Federer, who was watched by 5,000 fans at a practice session in Perth on Thursday.
"Expectations are low because I don't have the matches yet and it's going to be best-of-five from the get-go at the Australian Open.
"I'm happy I've got the Hopman Cup and I've got my three matches there to ease my way in."