South Australian police said they had been called to Phil Walsh's Adelaide home at 2 a.m. local time (4:30 GMT) on Friday and found the 55-year-old coach had died after suffering multiple knife wounds following an argument with his son.
"Police can confirm that the man murdered at Somerton Park in the early hours of the morning is Phil Walsh, coach of the Adelaide Crows," police said in a statement.
A police spokesman told reporters in Adelaide that Walsh's 26-year-old son had been arrested in a nearby suburb and detained for pyschological assessment. No charges had been laid.
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Walsh's wife had also suffered a "non-life threatening" leg injury and been taken to a medical centre, he added.
A successful player in the 1980s, Walsh took over as head coach of the Crows, two-times champions of the Australian Football League (AFL), during the off-season.
Australian Rules football, the country's indigenous sport, is hugely popular in the country's southern states where massive crowds attend championship matches.
The AFL is the country's richest sporting competition and in local terms, commands a following similar to top professional soccer leagues in Europe or the NFL in the United States.
Born in a country town in southern Victoria state, Walsh played 122 games for three championship teams before moving into coaching in the 1990s.
A self-described "hard arse" at training, Walsh was brought in to the Crows for his first senior role and charged with whipping the underperforming Adelaide team into shape.
An interview with a Melbourne newspaper, he revealed his computer had a screensaver of a street in Peru where he was struck and almost killed by a bus in 2012.
"That's my wake up call every day, as soon as I turn my computer on. Don't get too angry, Phil," he told the Herald Sun paper.
The news stunned the football-mad South Australia state capital, where crowds of 50,000 would regularly pack out the Adelaide Oval to watch the Crows.
"Tragic day for Crows supporters and sport in general ... A tragedy that people in Adelaide woke up to this morning," former Adelaide Crows chairman Bill Sanders told state radio ABC.
Distraught Crows players assembled at the club on Friday, as tributes from fans, rival teams and other Australian football competitions flooded social media.
"So sad to hear of Phil Walsh's death," Nathan Buckley, head coach of AFL team Collingwood and one of the game's finest players in the modern era.
"No sense to it. We are all flesh and blood. Love each other. Thoughts with all family and friends."
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