Because it's a still frame.
If you actually watch the video, you will see that there's a 4th player who is directly behind the player visible at the top of the screen. It's just freaky how he managed to be directly behind the player at that exact instant.
If there were only three on that side of the kick, that means there's only 10 players in the kick formation, and I don't think there's an R in existence in NCAA football who would blow the RFP on a free kick if one team only had 10 players on the field.
|