Hewitt has had a chaotic buildup to this season's opening grand slam tournament after his coach Roger Rasheed left him in the lurch by abruptly terminating their partnership last Friday.

The fiery Australian's build-up was hampered further when he had to pull out of this week's Sydney International after picking up a calf strain.

Despite the setbacks, Federer suggested it would be foolish to write off Hewitt's chances of becoming the first Australian man to triumph at the Open since 1976.

"He's health, obviously, that's my first concern," Federer told reporters in Melbourne before the invitational Kooyong Classic on Tuesday.

"I hope he's going to be ready in time for the Open. If he walks on court... I think he's definitely going to be tough to beat and (and he will be) a contender for the title, yes."

Instead of putting in the hours in a gym or on a court, Hewitt was left punching the numbers on his phone as he desperately searched to fill the void left by Rasheed.

With former players Wally Masur and Pat Rafter ruling themselves out of contention, Hewitt has drafted in his former Davis Cup team mate Scott Draper to guide him through the tournament.

Marat Safin knows only too well what Hewitt is going through having switched coaches a number of times himself but backed the Adelaide fighter to do well.

"He has a lot of experience as he won two grand slams," said the Russian, who beat Hewitt in the 2005 Melbourne Park final.

"He's definitely one of the dangers, if he can get over the injury."