We've seen no-hitters aplenty in this latest renaissance of pitching. What's to account for it? Is it the crackdown on steroids? I'm sure that's a factor. Is it the testing for amphetamines? I think that's a factor as well. But I think there may be one other factor coming into play that amplifies the effect of the testing. The 25 man roster.
As there has been an increased scrutiny on pitch counts as well as the increased focus on on-base percentage, batters have been taking more pitches and going deeper into counts. This results in starting pitchers not going as deep into games, bullpens being used more and subsequently a larger bullpen. Twenty-five years ago, teams would carry ten pitchers. Today, you usually see a staff of twelve. This left fifteen position players a generation ago which has been reduced to thirteen today.
In the national league, this leaves 5 replacement players on any given day (provided everyone is healthy and does not have any day-to-day ailments that would keep a player inactive, but would not furnish a trip to the disable list), which has also given rise to the value of a super-utility player. The backup catcher usually isn't a masher and teams are reluctant to spend this extra guy in case of an emergency. Among the four remaining players, who are the pinch hitting options when the pitchers spot comes up? There's the fourth outfielder, the backup corner infielder, the backup middle infielder (speaking in generalities - none of these would usually big a big bench threat - if they were, they'd have cracked the starting lineup). That leaves one extra player on a national league roster. One extra threat. With the limited bench options, most teams don't have the luxury of carrying a power threat off the bench such as a Matt Stairs who knows his job description is generally limited to one chance a game to make the best of it. By and large, with the larger bullpens - the regular bench is severely weakened.
When the regular bench is weakened, that leaves to options - play your starters just about every day (which may lead to more injuries or just a wearing down that will result in less production over the course of the season - remember, no more greenies or steroids). If you rest your starters, you create holes in your lineup that can be exploited by pitching around the threats and moving the lineup to the easier outs. Get to the pitchers spot in a close game and you're not seeing the pinch hitting threat you would have years ago.
Back in 1986, the Mets could pinch hit Kevin Mitchell, Howard Johnson, Lee Mazzilli, Tim Teufel/Wally Backman (depending on who was platooning that day) and Danny Heep. That's a pretty good mix before you'd even have to get down to Ed Hearn or Kevin Elster.
Today (and granted the 2011 Mets are not the 1986 team by any stretch), if you have the starting lineup in the game, you'd have the options of Willie Harris, Jerry Hairston, Justin Turner, Ronnie Paulino and Chin-lung Hu. Give any starter a day off and you've made your lineup shorter for a good pitcher to exploit.
You're always going to have the ham and eggers - but the bigger bullpens weakens the bench. Weaken the bench, you'll create more opportunities for the really good pitchers such as Halliday, Lincecum, Lee, etc to exploit the weaknesses and dominate the game.
I'm no saying this is a bad thing. I'm no saying this is a good thing. I'm just saying this may very well be a contributing factor.