Cy Walsh has pleaded not guilty by reason of mental incompetence to murdering his father, former Adelaide Crows coach Phil Walsh.
The 55-year-old died from multiple stab wounds at his Somerton Park home in July.
His wife, Meredith, was also taken to hospital and treated for a leg injury.
Their 26-year-old son was charged with murder and has been detained at the secure psychiatric facility James Nash House.
Walsh today appeared in Adelaide Magistrates Court through a video link and entered his plea through his lawyer.
Walsh did not speak during the hearing.
He was dressed in a green tracksuit, was clean shaven and his hair had been cut short and was slicked back.
He will now face the Supreme Court in February.
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