SUSA Rule 1.41. Infield Fly. A fair ball (not including a line drive) that can be caught by any fielder with ordinary effort when 1st and 2nd bases ior 1st, 2nd and 3rd bases are occupied with less than two outs. Any fielder can catch an infield fly. (Note: there is no stipulation about an infielder going onto the outfield grass to make the catch).

Question: The issue often arises when an infielder goes onto the outfield grass to catch a fly ball with runners on 1st and 2nd or when the bases are loaded, and fewer than 2 outs. Does the Infield Fly Rule apply and the batter is out, and runners' advance at their own risk?

I'll go with the term used "INFIELD" as being a position i.e. positions 1-6 & or 7 in some cases. Most all infielders move to the grass to catch balls.

If an infielder, in the umpire's judgment, can make a successful play (catch) on the ball with reasonable effort, the IFR applies. The defender retreating beyond the infield dirt/outfield grass line is irrelevant.