[mbyron]

In both instances the crucial judgment call is whether the fly ball "can be fielded by an infielder with ordinary effort." This us usually HTBT.

If the infielder has to turn around to run out for the catch, and makes it running away, then I'm generally not calling an infield fly. That's more than "ordinary effort."

The second case is probably an infield fly: I'm envisioning a high pop fly, with F3 backing up and F9 calling him off. Still, many of these will be HTBT.

Edited to add: if the second situation is the same as the first, then it's still not an infield fly, no matter who catches the ball. I was thinking of a different case.