What does “5-Man Defense” mean?

A 5-man defense in slo-pitch softball refers to a defensive alignment where a fifth infielder, often called the “middle infielder” or “5th man,” is added. This player typically positions themselves behind second base, covering the gaps between the traditional infielders and helping to defend against hard-hit balls up the middle. This strategy sacrifices an outfielder, leaving only three, to strengthen the infield defense.