A Miami Dolphins fan left Hard Rock Stadium last weekend without part of his toe -- when it was SMASHED TO BEJESUS in a freak accident during the game.

Jean Michaud was hanging out at a bar area inside the stadium while the Fins were taking on the Oakland Raiders when a heavy piece of marble slab fell off the bar and smashed his foot.

Michaud says he took off his shoe and noticed his big toe looked like a smashed grape ... and immediately called for help.

Paramedics raced to the scene and began to treat Michaud on the spot. He was transported to a nearby hospital where he underwent surgery. The big toe was partially amputated. He was discharged the next day.

It's unclear how the slab fell off the bar and onto Michaud's foot -- but he claims he wasn't leaning on it or messing with it in any way. He's since hired a lawyer and is weighing his legal options.

We reached out to the stadium and the Dolphins for comment, but haven't heard back from either party.