The 1990 and '91 seasons saw a sudden surge in no-no's, with seven each year -- both records for the modern era. But there were none in 1989 and just one in 1992.
The last three years of the 1960s saw a spike in hitless performances, with 15, but the feat slowly trailed off after that. The 1916-17 seasons offered a similar spike that seemingly came out of nowhere.
Angels manager Mike Scioscia caught Fernando Valenzuela's no-hitter for the Dodgers on June 29, 1990, the same night Oakland's Dave Stewart held the Blue Jays without a hit. That was the only time two no-hitters were thrown on the same day.
"Did anybody ever figure out why in '90 and '91 there were more?" Scioscia pondered on Wednesday. "I don't know if there's really a rhyme or a reason to it."
There very well may not be. But that hasn't stopped experts from trying to figure out why 2012 was the quickest season to five no-hitters in 95 years.
Already, Phil Humber of the White Sox and the Giants' Matt Cain notched the 21st and 22nd perfect games, respectively, in Major League history (postseason included). The Angels' Jered Weaver, the Mets' Johan Santana and a combination of six Mariners pitchers round out the list of no-hitters this season -- bringing the count to 277 in MLB history.
Scioscia postulated that the sudden rise may be a result of a plethora of talented pitchers getting a few breaks just when they need them.
But one of Scioscia's pitchers was quick to debunk that idea.
"I don't think so, because there's a lot of great hitters out there," said Ervin Santana, who tossed a no-no of his own last July and flirted with perfection in tossing a one-hitter on Saturday. "It's not easy to face those kinds of guys ... It's just one of those things. I think this year is just one of the years where everybody's doing it. The pitchers are just executing the pitches where they want."
Giants manager Bruce Bochy added that scouting technology has helped pitchers analyze the tendencies of hitters more so than the other way around. He also is a believer in the end-of-steroids theory.
MLB and the players' association adopted the Joint Drug Prevention and Treatment Program in 2006. From 1992-2004, there were 24 no-hitters thrown. In the past three years alone there have been more than half that many -- 14.
"Well, it's a cleaner game, maybe that does have something to do with it," Bochy said. "I don't know. Obviously there's something going on. But I do know that when you look out at all these teams, you see some great arms."
The one theory that is almost impossible to dispute is the effects of expansion. Obviously no-hitters should occur more frequently now than they did decades ago because there are more teams, and, as a result, more games and chances for history to be made.
Expansion also brought with it another potential reason for the rise of the no-hitter. A great pitcher is a great pitcher, regardless of the era, but with more teams, the talent pool of hitters is divvied up to a greater amount of clubs.
Those hitters have also been striking out more frequently in recent years, meaning less of a chance of a ground ball squeaking through the infield for that fateful first hit.
But there is still no statistical evidence that the influx in no-hitters can be attributed with certainty to any of the proposed theories. History tells us that the feat comes and goes and is likely to stay that way.
"I think it's just one of those weird mathematical things," said Angels catcher Chris Iannetta, who caught Weaver's no-hitter against the Twins on May 2. "It's just a statistical anomaly where a bunch are grouped together. Then it will fade out, and somewhere down the road we'll get a few more, and we'll be talking about it again."
Scioscia, too, has noticed that trend, saying he heard similar chatter as during the early-'90s stretch of 14 no-hitters in two years.
"Has anybody ever realized why?" Scioscia said, referring to a reason behind the various eras of no-hitters in the past.
The short answer to his question is no, which led him to draw the obvious conclusion.
"Then we probably won't realize why this time either," Scioscia said.