Tigers slugger Victor Martinez and a fan in the right-field bleachers put MLB's instant replay system to the test in the bottom of the seventh of Game 4. Martinez hit a high drive to right that Josh Reddick appeared to have a bead on, but then this happened:
The ball was obviously interfered with by the fan -- hitting him in the hands -- and the trajectory has it clearing the yellow line, but it's difficult to say whether Reddick would have caught the ball had the guy not put his hands out.
Here's a still image of the moment before it hits:
The home run knots the game at 4-4 in the seventh.