Fremantle forward Cam McCarthy is in hospital after collapsing during non-contact training at the AFL club.
The 25-year-old was taken to hospital in ambulance and will undergo tests to determine what caused his collapse.
"Cam was training really well with a small group of teammates in a non-contact session this morning when he suddenly collapsed on the ground," Dockers football boss Peter Bell said on Wednesday.
"He was immediately assessed by our medical staff and an ambulance was called.
"Cam was subsequently admitted to hospital, where he is undergoing further assessment and tests to determine the possible cause of the collapse and what treatment will be required."
Bell says the club will provide McCarthy and his family with the necessary care and support and will comment further in due course.
Dockers coach Justin Longmuir is scheduled to address the media later on Wednesday.
More to come.