It’s not often that Mariano Rivera blows a save, let alone back-to-back saves, which made yesterday’s ninth inning meltdown that much harder to swallow. Andy at the B-R Blog lists all of Mo’s back-to-back blown saves, something he’s done just eight times in his 14+ years as closer. Exactly half of those eight sets have come in April while the rest occurred in July and August (twice each). He also blew back-to-back saves twice in 1997, so it’s happened just six times in the last 13+ years.
Although it doesn’t appear to be random, I don’t think there’s nearly enough evidence here to say that Mo struggles in particular months for whatever reason. Is it worth nothing that there’s essentially no difference between Rivera’s ERA and FIP in March/April (2.26 ERA and 2.84, respectively) than there is during the rest of the season (2.22 ERA, 2.75 FIP). What do you think, coincidence, or something more?