For more than 100 years, baseball looked pretty much the same from the grandstands. There were three players spread in the outfield, a pitcher on the mound, a catcher behind the plate, and four infielders neatly aligned, two on each side of second base.

But a radical reworking of defensive principles is reshaping the way the old game is played, and even the way it looks. If you cannot find the third baseman, he might be the one standing in shallow right field. The second baseman? That’s him on the other side of the diamond, next to the shortstop.

Some baseball positions as they have long been known are changing before our eyes. The cause is the infield shift, a phenomenon exploding this year as more teams are using statistical analysis and embracing a dynamic approach to previously static defenses.

Now, armed with evidence that shows how a batter has a propensity to hit the ball to certain parts of the field, teams will position their infielders accordingly — at times taking them far from their traditional spots.