Derry City captain Ryan McBride has died, the Irish Football Association has said.
The 27-year-old defender is thought to have died at home on Sunday evening, according to reports.
A cause of death is not yet known.
The Irish FA tweeted: "Thoughts tonight with the family of Ryan McBride and everyone involved with @derrycityfc."
His death comes a day after McBride led his team to a 4-0 victory over Drogheda United.
The defender will be remembered as one of the League of Ireland Premier Division side's all-time greats, the club said.
"Derry City Football Club is deeply saddened by the untimely death of our captain, Ryan McBride," read a statement on the club's official Facebook page.
"Our prayers and thoughts are with his father, Lexie, his sisters Colleen, Siuinin and Caitlain, and his partner Mairead who are heartbroken at his loss.
"We are also conscious of his team-mates and our management and support staff. Ryan was a player and a great captain but he was also their friend and team-mate. They are deeply shocked and will miss his inspiration and his leadership.
"Our supporters are also shocked and saddened. To them, Ryan was Derry City through and through. The commitment and passion he brought on to the field is the bond that binds player and supporter.
"In the hearts and minds of all of us and long into the future Ryan McBride will be remembered as one of the greats of Derry City Football Club.
"We are also conscious that this is the anniversary of the death of the members of the McGrotty and Daniels family in Buncrana and it is only a short time since we remembered Mark Farren's death.
"It is at times like this that we are reminded that our club is also a community of people. As in the past, that community will come together to comfort and support Ryan's family.
"In the coming days and weeks we will grieve the loss of our captain and our friend.
"Sometime in the future, when we have got past the initial shock and have had the proper space to grieve his loss, we will find a way to celebrate his life.
"We will remember his civility and humility off the field, his commitment and passion on it and the deep love he carried in his heart for Derry City Football Club."
Drogheda United said on Twitter that they "would like to offer our deepest condolences to @derrycityfc on the sudden passing of their captain Ryan McBride".
It is the second tragedy to hit the club in just over a year following news that record goalscorer Mark Farren had passed away aged 33 after battling a brain tumour.
Derry's fixture with Limerick, due to be played on Tuesday night, may be postponed following the news of McBride's death.
Tributes pour in for McBride
Our deepest sympathies to all @derrycityfc on the sudden passing of Ryan McBride. Our thoughts are with his family and friends. RIP— Cork City FC (@CorkCityFC) March 19, 2017
Deepest sympathy to the family of Ryan McBride and to everyone at @derrycityfc on the sudden passing of their club captain.— Linfield FC (@OfficialBlues) March 19, 2017