outfielders positioned at edge of infield

Question
Our men's slow pitch league changed to wood bats last year. This year, a few teams in the league have begun to move one of the outfielders (typically the short fielder if they are positioned that way)directly behind 2nd base for certain batters. Is there any specific rule that prohibits this or a rule that states a specific distance from the infield that an outfielder must be positioned? Thanks!

Answer
Good morning Kevin,

In men's or women's softball the only requirement is that all defensive players except the catcher be in fair territory.  There are quite a few teams that play a "5 man" infield.

They can put all 9 on the infield if they want to.

Mark