Completely legal in men's slow pitch and women's slow pitch. Not legal in coed.
There are only three rules regarding the positioning of fielders in men's or women's slow pitch.
1 - All fielders (except the catcher) must be in fair territory when the pitcher delivers the pitch.
2 - No fielder may take a position in the batter's line of vision to the pitcher.
3 - You must have a pitcher and a catcher.
Beyond that, they can have 8 outfielders or 8 infielders (excluding pitcher and catcher) for all I care, so long as they meet all 3 rules above.