LeBron James revealed he "pretty much played the last three games with a broken hand" after the Cleveland Cavaliers were swept by the Golden State Warriors in the NBA Finals.

James suffered his sixth Finals defeat following the Cavaliers' 108-85 game-four loss to reigning champions the Warriors in Cleveland on Friday.

The Cavaliers were outclassed on home court at Quicken Loans Arena and reports immediately emerged of a serious hand injury to James, who reportedly punched a blackboard after Cleveland's dramatic game-one defeat.

James – a three-time NBA champion – scored 51 points but the Cavaliers suffered a 124-114 overtime loss following a bizarre brain fade from team-mate J.R. Smith, who dribbled the ball out in regulation after collecting the offensive rebound with the scores tied.

"Self-inflicted ... after game one," James told reporters after finishing with 23 points. "Very emotional ... the way we played, the calls that were made, I had emotions that the game was taken away from us.

"Pretty much played the last three games with a broken hand."

James received a heartfelt standing ovation as he left the game-four blowout early to allow the Cleveland crowd to say goodbye, potentially.

The 33-year-old is tipped to enter free agency during the off-season – with the Philadelphia 76ers, Los Angeles Lakers and Houston Rockets possible destinations – and he came out of the clash four minutes from the end to chants of "MVP! MVP!".

Asked about his future post-match, James – who returned to the Cavaliers in 2014 and delivered a championship in 2016 – insisted his decision will revolve around his family.

"The one thing that I've always done is obviously consider my family," the four-time MVP said.

"Especially where my boys are at this point of their age. They were a lot younger the last time I made a decision like this four years ago.

"Teenage boy, pre-teen and a little girl that wasn't around last time as well.

"So I'll sit down and consider everything. My family is a huge part of whatever I decide to do."