On the on-side kick late in the fourth quarter, the Referee was covering B's restraining line, and made the call that B recovered the kick. In a six-in-the-box mechanic for a seven-man crew, R covers B's goal line. So was the BJ replaced, or did the crew go to six-man mechanics? And in six-man mechanics, who covers B's goal line in an onside-kick situation?

7 man mechanics The injured B was replaced by the alternate who was an R and had that shirt The R you saw was the replacement for the B

If you're this worried (not that you don't have good reason to be), I'd look into getting some good STD insurance. You should be able to get an annual policy for less than you could earn in a single day working youth football.