Bluff or Not?

Scott Ian fired a bet on a board of {Q-Diamonds}

and was called by Jon Favaloro. The pot sat at approximately 17,000 when the river came the {8-Diamonds}

. Ian tipped his head down and studied his own chip stack. After a few moments, he raised his chin and announced that he was all in. The bet was for 12,025. Favaloro tanked and eventually called the clock on himself. With about 10 seconds left on the clock, he announced a fold.

He asked Ian to show as the pot was pushed his way. Ian showed only the {8-Hearts}