Maldonado: 4.43 CERA entering today's game (221 innings)
Rivera's: 2.90 (115 innings)
The thing is, Maldonado's pitch calling is visibly bad and worse than Rivera's. So these numbers are no fluke.
Can Rivera please be the starting catcher? Similar offensively to Maldonado, and his pitch calling is terrific. This staff's ERA is around 1.5 runs lower with him catching compared to Maldonado.
Maldonado's catcher's ERA before today's game: 4.45 (204 innings caught)
Rivera's catcher's ERA: 3.14 (106 innings caught)
I can't say this is meaningless based on watching the games.