ADELAIDE has revealed that assistant coach Dean Bailey is battling cancer and has been granted indefinite leave from the club.

The Crows' strategy and innovation coach was admitted to hospital last week after suffering from a worsening cough and liquid was found in his left lung.

While that issue has been alleviated, the cause was discovered to be cancer in his chest.

Bailey has begun extensive testing in an attempt to identify the type of cancer he has, after which he will immediately start treatment.

Crows CEO Steven Trigg said the club's primary focus was to support Bailey and his family.

Trigg said Bailey's absence would be managed until the club had a clearer idea of his ability to return to work.

"It's a real challenge for Dean and for his family and our priority as a club is, first and foremost, to support Dean through it and to support his family," Trigg said.

"I don't expect to see too much of him before Christmas as he puts the absolute priority on himself and getting himself right.

"We've got plenty of resources to be able to cover his absence pre-Christmas.

"We'll be in a better position by Christmas to understand how that treatment's going, what the state of play is and what our response would be in an ongoing sense."