The 37-year-old has been caring for his ill wife since January but faces West Indies in the Kuala Lumpur tri-series.
"I've had a good break. I've been training hard and working on a few things that I wanted to touch up on.
"To be honest I'm feeling as good as ever in the pre-season compared to other years. I'm further ahead than I've been in the past," McGrath said.
The tall seamer has taken 331 wickets at an average of 22.43 in 221 One-day Internationals.
And Ricky Ponting is confident his premier fast bowler will have few problems easing himself back into the international scene in what is a warm-up for next month's ICC Champions Trophy.
"I've got the highest expectations of Glenn coming back," the skipper said. "He's a been such a great bowler for such a long period of time, he'll just slot right back in and do the job for us." It is not just McGrath, who will be making a comeback, with Australia playing their first game since the tour of Bangladesh in April.
Ponting said his 18-man squad would be rotated, with youngsters mixed with experienced players. The first experiment sees Simon Katich and Phil Jaques open in the absence of Adam Gilchrist, who is resting back home, and Matthew Hayden.
New South Wales wicket-keeper Brad Haddin takes over from Gilchrist behind the stumps, while Mark Cosgrove, Dan Cullen and Mitchell Johnson are also brought in.
"We are looking at giving equal play to all our players. Some guys will play two games, others three," Ponting added. Champions Trophy holders West Indies' last one-day series was a convincing 4-1 triumph over India, which vice-captain Ramnaresh Sarwan says showed the team is beginning to gel as a unit.
"We will be the first to admit that we have been inconsistent over the past few years but we're starting to play some good one-day cricket.
"What we have been trying to do leading in to the Champions Trophy, and the World Cup, is to stick to a core group of players and not do too much chopping and changing.
The tournament, which also features India, will see the teams play each other twice before a final on 24 September. All seven games will be day-night affairs at the Kinrara Oval.