As first reported by ESPN's Brian Windhorst, LeBron James has been nursing a significant right hand injury after he punched a black board in the locker room following Cleveland's Game 1 loss on May 31.

Windhorst tweeted that James had two MRI's and has been wearing a soft cast. He said that James is not using the injury as an excuse but chose to keep it quiet to prevent the Warriors from knowing about it.

Speaking to media after Game 4, James confirmed the injury.

"Self-inflicted. Post-game, after Game 1," explained James. 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 was visibly upset on court after J.R. Smith's gaffe in the closing seconds of regulation in Game 1. Smith grabbed a rebound with seconds remaining in a tie game but apparently thinking that his team was winning, chose to run out the clock instead of attempting a shot from in close. The Cavaliers went on to lose the road game in overtime.

In Games 2, 3 and 4, James scored 29, 33 and 23 points, respectively, as his team was swept by Golden State.