Two things happened this offseason. The rosters expanded to 26 players and the White Sox signed a top tier hitting catcher. So it is quite obvious that Yasmani Grandal and James McCann will be the catchers for the 2020 season. However, a number of people also think Zack Collins will be rostered as a 3rd catcher. You may be in favor of this, I am not, but there is one argument I see for this that makes my head hurt.
I see people on the internet and some I’ve spoken to in person say that a 3rd catcher is key because it gives you the option to DH Grandal when McCann catches. The idea here is that you don’t want to use a catcher as DH because if your starting catcher gets hurt and Grandal has to go in to catch, the DH position switches to the pitcher. This is a fact, but it’s so uncommon, I don’t know why you’d worry about it.
The most recent data I could find on league wide catcher injuries is from this Johns Hopkins study. The data shows there were 134 reported catcher injuries from 2001 – 2010. This is 13.4 injuries across the league per year. Now I understand that doesn’t include catchers just leaving the game nor does it include the newer concussion rules. So let’s increase this and let’s be generous. We’ll say there are 20 times that many injuries now. Round up to 270 across the league and you have 9 per team per year. Now, the catching duties are split, so Grandal would be more likely to get those injuries. But let’s put the split in favor of McCann and say he gets knocked out of 5 games. And each time, it’s early enough that there are 3 plate appearances required. We’ll also pretend the Sox never pinch hit for the pitcher. In this scenario, you’ve rostered a 3rd catcher to handle these 15 plate appearances. Seems like a bad idea or at the very least, unnecessary.