Infield Fly Rule
 

Had a JV game in which the batter hit a low line drive to the second baseman. The coach come out and wanted to know why I did not call the infield fly. I explained to him that I did not think that it was an easy catch for the second baseman to make. Did I make the correct call.

Sounds like you made the correct call, but your response to the coach was incorrect. You don't have to judge the relative ease with which the fielder can catch a line drive. The infield fly rule only applies to fly balls. A line drive is not a fly ball.

I would have said, "Coach, for me to call the infield fly rule, there has to be a fly ball. That was a line drive."