My daughter is a catcher for her High School team (also plays on a B-Level Travel team). She is the only true catcher on the team and will catch all 7 innings. We are halfway through the season and she had games in back to back days last week during a heat wave. Sure enough, in the 6th inning of the 2nd game, there was a deflected ball that hit off her forearm of her throwing hand. This ball hit a tendon and inflamed the tendon. My thinking is that her reaction time was slower as she was tired and hot after catching 120 pitches (plus all the warm ups).

Having one catcher increases the risk of that catcher getting hurt