Keith Law, FWIW, says catcher ERA is worthless. I'm not convinced, though nemodomi can pop off again where his input is not requested and insert his favorite phrase, SSS. It does seem if you're a poor receiver or game-caller, that that ought to show up in your mound counterpart's statistics somewhere, but 400 to 900 innings caught a season may well fit the parameters of SSS, especially when you're not the dominant factor in that equation.