If you’re someone who has been watching baseball avidly for more than a decade, chances are you have certain instinctive reactions to the ball hitting the bat. But there’s one that you’ve had to reset: whether or not a ground ball up the middle (past the pitcher’s mound) is going to produce a baserunner by hit or error.

Let’s quantify that just to be able to better understand the difference.

If you grew up in a time in which shifts were highly unusual, the ball up the middle consistently produced a positive result for the batter.

In 2010, there were just over 3,300 ground balls that were hit in-between the two lines shown in this image. This was a season when shifting was highly unusual.

Batters reached base on those balls 70% of the time.

But in 2019, it’s a different game. There have been just over 2,000 of those types of ground balls hit there.

Batters are reaching base only 48% of the time.

Teams have grown more successful at protecting this part of the field, regardless of whether a shift is on, as this chart shows.

Batted ball distributions are such that an individual player is only going to be minimally affected by this.

The one “suffering” the most this season is Alex Bregman, who has reached in 2-of-12 instances in which he hit a ground ball up the middle (he reached for the second time over the weekend).

This jibes with how defenses are playing Bregman.

In 2018, he was defended straight up on about 70% of the ground balls and short line drives he hit. In 2019, that has dropped to an almost 50-50 split.

We mentioned Bregman is 2-for-12 in reaching on balls up the middle this season. Prior to this season, he was 16-for-22 in reaching base when hitting a ground ball there.

Bregman enters the day hitting .269. If he had gotten hits on even five more ground balls up the middle, he’d be batting .283, almost exactly what he batted in 2017 and 2018.

Longer term, Giancarlo Stanton can do enough damage to where hitting ground balls up the middle isn’t that important to him. He’s reached 23 percent of the time when hitting a ball over the middle the last four seasons, lowest of anyone with at least 30 ground balls. You would figure the top of the list features hitters who are unpredictable in their hitting patterns, meaning the defense can’t shift him. Hunter Pence is one. He’s at the top, having reached 83% of the time (45-of-54).

Pence is one of the fortunate ones. More hitters are finding it harder to push balls through. And more fans are having to get used to seeing those hitters repeatedly frustrated.