EE WAS ASSISTING A COWORKER IN THE REPLACEMENT OF AN IDLER ROLLER. EE PLACED HIS SIDE OF THE ROLLER INTO THE BRACKET AND PLACED HIS HAND ON A WOODEN BLOCK JUST BELOW THE ROLLER. THE COWORKER MOVED HIS SIDE OF THE ROLLER TO GET IT SET INTO THE BRACKET. THIS CAUSED THE ROLLER TO FALL AND HIT EE'S HAND THAT WAS ON THE BLOCK. CUT FINGER.