Strikeouts: A funny thing happened over the past couple of decades. Even as offense spiked, so did strikeouts.
There's no denying that the stigma attached to striking out has diminished greatly in recent years, but whether it's a matter of culture, a reaction to a high-power offensive environment or just cyclical, batters strike out more today than they ever have. More than 18 percent of all plate appearances ended in a strikeout in both 2010 and 2011. That's up from 16.5 percent as recently as 2005.
From 1986-93, the rate hovered at around 15 percent, and from 1978-81, it never topped 13 percent. Even in the pitching-dominated 1960s, the rate never topped 16.1 percent. All of which is to say that the one thing you have to do in order to get a hit -- put the ball in play -- is happening less often. So it only makes sense that pitchers have a greater chance of going an entire game without giving one up.
That's true even in a high-offense era. And relative to historic norms, this is still a fairly high-offense era, but it's a fairly high-offense era with a lot of strikeouts. So runs remain at a reasonably high level, but on any given night, the high strikeout rate means a greater chance at a game with no hits.
Defense: Though fewer and fewer balls are being put in play, teams are getting smarter about how to make sure the balls that do go into play turn into outs. The last frontier of baseball analysis is the evaluation of defense, but clubs are getting much better at it.
Many teams have their own in-house methods for rating defense, and the more they study it, it only follows that they'll get better. A natural consequence of that, surely, is better defensive players being on the field for the average big league team.
In addition, those players are in better position than ever before. Clubs are becoming more and more aggressive about shifting their defenders' positions, led by the Rays and Blue Jays, and fielders have more and more video to use for studying hitters' tendencies.
It shows up, to an extent, in the stats. The overall Major League batting average on balls in play fell in each of the past four years, and it's about even so far in 2012 relative to 2011. Those numbers are still well above where they historically stood prior to the 1994 expansion, when offense really took off, but there's nonetheless a clear trend of balls in play turning into outs more often.
The ballparks: Although plenty of hitter-friendly ballparks exist, quite a few of those that have come into existence in recent years are pitchers' parks. Look at Target Field, Citi Field and AT&T Park, to name a few, plus the Rays' home, Tropicana Field, keeps becoming more pitcher friendly. So there are more places that are conducive to a historic night.
And the research bears it out somewhat. Ten of the past 15 no-hitters have taken place at parks that would be called pitchers' parks: Angel Stadium, Safeco Field (twice), Tropicana Field (twice), O.Co Coliseum, Sun Life Stadium, AT&T Park (twice) and Citi Field. That doesn't explain all of them, not at all. But it doesn't hurt, either.
PEDs: This one is by far the hardest to quantify. After all, plenty of pitchers have been suspended for using illegal performance-enhancing drugs, and even some of the hitters who were caught weren't exactly power hitters.
Still, the boom in no-nos has come since the advent of drug testing. The punitive phase of the testing program began in 2004, and the surge in no-hitters began in 2007. It's certainly difficult to prove the absence of a connection, even if it's also hard to pin down the presence of one.
Statistical noise: Unfortunately, the least satisfying answer is also likely the most correct one. Sometimes poetry must give way to prose, and in the case of the spate of no-nos, that appears to be the case.
Though the surge in no-hitters grabs our attention, it's not statistically significant. When you play nearly 2,500 games per season (the regular season calls for 2,430, then there's the postseason), a lot of strange and interesting things can happen. And the number of no-hitters we've had in recent years doesn't fall outside the range of what could normally be expected to happen in some seasons out of decades upon decades of baseball.
If we keep seeing three, four, five no-hitters every year for the next five or 10 years, that will be a different story. For now, though, there's reason to believe it's just a blip in the long history of the game. An entertaining blip, but a blip nonetheless.