The other day Jay Nordlinger tweeted out this column by Detroit sportswriter Chris McCosky, who thinks that hitters would strike out less if they tried harder when they had two strikes on them. McCosky agrees with Tigers manager Ron Gardenhire, who says that “good hitters on good teams, they shorten their swing with two strikes and put the ball in play in big situations.”

But the main reason that hitters are striking out more is that the pitching is getting harder to hit. Pitchers have more room to improve by adjusting their mechanics, which come down to grip and delivery. A recent trend among starters, for example, is to forgo the windup and pitch only from the stretch, which helps their control. Hitting, by contrast, depends heavily on reflexes and eyesight, and it’s hard to improve on what you were born with in those departments. The average velocity of fastballs is always increasing. What’s worse, for the hitters, is that they’ve been seeing more curveballs lately.

A lot of breaking pitches that are called strikes now wouldn’t have been 20 years ago. In the late 1990s, MLB began to clamp down on the idea that an umpire could have a “signature” strike zone. At the time, most of the talk was that the zone would be higher and narrower, but “I think where you’ll see a difference,” American League umpire Rocky Roe predicted, “is the real good curveball, where the arc is coming through the strike zone. In the past we would have had a tendency to call it a ball.” When MLB started insisting that the ump had to start calling strikes strikes even when they were unhittable, pitchers began throwing more curves.

A third reason that MLB pitching is getting harder to hit: Managers now use their pitching staffs more shrewdly than in the past, or at least some are. Everyone knows that the performance of most pitchers declines noticeably the second time through the batting order. Finally, organized baseball is discovering the concept of the opener.