Infield fly if fair

Question
Runners on First and second no out. Ball is clearly a foul ball between third and Home. My catcher and 3rd base go after pop up until the home plate umpire calls Infield fly if fair. The both stop as soon as they here the call.
Isn't the field umpire supposed to make that call? I have never heard and infield fly called that way

Answer
Jack,

No, either umpire can make the IFR call and yes I have heard it called that way.  I am not sure if that is a prescribed mechanic anywhere.  I wouldn't call it that way.  I would just say infield fly and hesitate on calling the batter out based on where the ball landed if it wasn't caught.

If it indeed is over foul territory and the ball isn't caught, then you just have a foul ball and no runners are in jeapordy and there is no reason for the batter to be out.  If it is caught the batter is out and the runners are free to advance with a tag up just like an IF caught in fair territory.

I would have a talk with your catcher and 3rd base.  The umpire didn't say anything that would cause a player not to try and catch the ball.

Tom