Melbourne forward Liam Jurrah is in an Alice Springs jail after the AFL player was involved in an incident allegedly involving a machete.
Local police said two 23-year-old men were arrested following an incident on Wednesday night at the nearby Little Sisters Town Camp.
The Demons announced on Monday that they had granted Jurrah personal leave so he could return to Central Australia and help with family and community issues.
"Police were called around midnight to attend a disturbance ... on arrival, police found a 35-year-old man with serious head injuries alleged to have been inflicted by a machete," Northern Territory police said in a statement on Thursday.
"Two men aged 23 years are currently in police custody with investigations continuing."
Melbourne also confirmed that Jurrah was in custody and that no charges had been laid.
"We are not aware of any further information and, therefore, not in a position to make comment at this time," the Demons said in a statement.
The Demons are expected to send a club official to Alice Springs soon.
Alice Springs police are investigating whether there is a link between the incident involving Jurrah and another that happened near Alice Springs around the same time.
A 15-year-old was hospitalised with severe head injuries and a 30-year-old woman is in custody.
Before Wednesday night's incident, the Demons had been hopeful that Jurrah would be back at the club within a week.
Jurrah is an initiated member of the Warlpiri people who live in Yuendumu, a community about 300km northwest of Alice Springs.
He is the first player from a remote central Australian community to play in the AFL.
There have been reports of deep-seated and violent disputes in the Yuendumu community.
In announcing Jurrah's leave on Monday, Melbourne said he was going home "to support his family and community through a challenging period".
New Demons coach Mark Neeld had said last week that Jurrah would probably be out of action until at least round one of the regular season as he recovers from off-season wrist surgery.
Jurrah was Melbourne's leading goalkicker last season, with 40 from 18 games.
He has kicked 81 goals in 35 games since making his senior debut three years ago.