Trescothick walked out on his team nine days before the start of the series after a recurrence of a stress-related illness that has touched the nerves of Australia's professional athletes.
Despite the intense rivalry on the field, the Australian and English teams have strong personal bonds off the pitch and Trescothick's plight has been felt as deeply in Australia as his homeland.
Australia captain Ricky Ponting said he was deeply saddened by the news of Trescothick's mental breakdown.
"All we can do is wish him well," Ponting told reporters. "If it's an illness that's going to keep him out of such a big series as this, it's obviously pretty significant."
Australian vice-captain Adam Gilchrist said cricketers were always vulnerable to bouts of depression because of the long periods they spend away from family and friends.
"It is a demanding lifestyle, particularly as an individual, and then you throw in family and children...there is a lot of sacrifices that need to be made," Gilchrist said.
"On top of all that there is the pressure and the intense scrutiny you come under every time you present yourself out on the field in front of millions and millions of people.
"It can start to play tricks on your mind, or your mind can start to wander."
Depression has become an increasing global problem in sport with more and more athletes turning to psychologists to help deal with the pressures and expectations.
Trescothick's breakdown was major news in soccer-mad Britain and Australia, with his situation also drawing widespread sympathy from the country's top golfers who are in Sydney for the Australian Open championship.
LIFE'S AMBITION
Steve Bowditch, a promising young player who achieved his life's ambition by qualifying for the U.S. PGA Tour this year, said his dreams were shattered when he developed depression.
The 23-year-old, who is back in Australia trying to rebuild his life and sporting career, said he became so depressed that he contemplated suicide.
"It scares you what goes through your mind," he told reporters.
"Everything seemed so small and so dark, and I realised it was time to get help."
Stuart Appleby also revealed that he needed professional help to cope after his wife was killed in a freak car accident in London in 1998.
"Lack of knowing if there was a future," he said. "A simple problem was no longer simple. You can imagine if that goes on for years and years and years and no one recognises it."
