We've often wondered how many injuries result from thrown bats in Major League Baseball. Once they've hit the ball, no slugger really cares where their bat ends up. The focus is on making it to first base, not the welfare of the people around you. You just toss it and run, which surely has got to end in disaster every now and again.
For this poor spectator, it's probably the last play he saw in the match. At that speed, a solid bat has got to do some serious damage. He had no idea it was coming for him, either - just look at the reaction of the crowd around him. For a bat to make it that many rows back, you've got to assume it was almost intentional. Either that or the batter had some seriously greasy hands.