Panathinaikos defender George Baldock, a former Greece international who also played for Sheffield United for seven seasons, has been found dead in his Athens home at the age of 31.

Baldock's death was confirmed on Wednesday night (Thursday AEST) and a family statement read: "We can confirm that George has sadly passed away. As a family we are in shock at this terrible loss. We ask please that the media respect our privacy at this time."

Britain-born Baldock was called up for Greece in 2022 and played 12 matches, the last in March in the Greek loss on penalties to Georgia in the Euro 2024 play-offs.

Baldock was not in Greece's squad for Thursday's UEFA Nations League game against England.

He had played for his Greek club side Panathinaikos in Sunday's 0-0 draw with Olympiacos.

Baldock joined Sheffield United in 2017 and helped the club earn promotion to the Premier League twice, in 2019 and 2023.

He joined Panathinaikos in May, on a three-year contract, after Sheffield United were again relegated to England's second division.

"Sheffield United Football Club is shocked and extremely saddened to learn of the passing of former player, George Baldock," the English club said on social media.

"The defender left the club in the summer after seven years at Bramall Lane and was extremely popular with supporters, staff and team-mates who pulled on a red and white shirt alongside him."

Tributes were pouring in from around the world after news broke about his death.

England and Manchester United defender Harry Maguire, a former Sheffield United player, posted a photograph of Baldock on Instagram with a broken heart emoji and "RIP".

The Greek national team also paid tribute to Baldock.

"With deep sadness and pain, the national team and the Hellenic Football Federation say goodbye to George Baldock," the Greek team said on Facebook.

"There are no words to describe the human pain caused by the news of the untimely loss of one of our young people. The moment calls for silence. Condolences to his family. Condolences from his second family. Goodbye."

England's Football Association expressed its devastation at Baldock's death.

"We are devastated to learn of the passing of George Baldock at the age of 31. Our thoughts and deepest condolences are with George's family, friends and team-mates at club and country," an FA statement read.

An England team statement added: "We're extremely saddened by the passing of George Baldock.

"George was close to many of our players, and represented Greece - our opponents on Thursday night. We're thinking of George's family, friends and team-mates at club and country at this difficult time."

Buckinghamshire-born Baldock started his career at MK Dons and went on to play more than 100 times for the club.

A lengthy spell at MK Dons included numerous loan spells away, with two stints at Oxford before he signed for Sheffield United in 2017.

- with PA, agencies