There is a rule that says that any time a team makes a fair catch, it has the right to a free kick of the ball, which the opponent is not allowed to attempt to block.

Chargers' Harbaugh relishes rare fair catch kick aft...

我昨天有看這場，第一次看到這個規則

看推文大家也都一頭霧水，美式足球真是博大精深～