The reasons for more no-hitters are the same reasons why offense in general is down:
• the emphasis on movement over velocity for pitchers (hence the popularity of the two-seamer and cutter)
• more advanced defensive positioning based on analytics
• more sophisticated scouting reports
• less familiarity hitters have with pitchers (because specialized bullpens and injuries have created the need for more pitchers than ever before; the smaller the batter-pitcher history, the more the pitcher gets an edge)
• the acceptance of strikeouts in the culture of hitting
• a demand for pitching that has encouraged youth players to concentrate on pitching over a position
• the intense training of youth pitchers (many of whom become “pitcher-only” designates at an early age)
• a small wave of pitcher-friendly new ballparks
• a first generation of players who are tested for performance-enhancing drugs and amphetamines, which has seen a drop in power and durability (more days of rest and DL days).
I said it after Humber’s perfect game and I’ll say it after Weaver’s no-hitter: get ready for more no-nos. At the rate we’re going these past three years, you can expect three or four more no-hitters before the season is over.