Cardiff defender Sol Bamba has been diagnosed with Non-Hodgkin lymphoma.
The 35-year-old defender has started chemotherapy and will be supported by the Bluebirds' medical team.
A club statement read: "We are saddened to inform supporters that Sol Bamba has been diagnosed with Non-Hodgkin lymphoma.
"With the close support of the club's medical team, Sol has immediately started a course of chemotherapy treatment.
"Universally admired by team-mates, staff and supporters in the Welsh capital, Sol has begun his battle in typically positive spirits and will continue to be an integral part of the Bluebirds family.
"During treatment, Sol will support his team-mates at matches and our younger players within the Academy, with whom he will continue his coaching development.
"All future updates on Sol's progress will be provided only via official club channels.
"While we request privacy for him and his family at this time, messages of support to be passed on to Sol may be sent to club@cardiffcityfc.co.uk. We are all with you, Sol."
Bamba, who started his career at Paris St Germain, has made six appearances for Cardiff this season – the last coming against Birmingham in December – and 117 in total, scoring 10 goals.
He helped the club into the Premier League in 2018 and has also had spells at Hibernian and Leicester, moving to the Bluebirds from Leeds in 2016.