The legend is that in the days before supermarkets, small grocery store owners placed their tins of canned corn on the top shelves because they stored well and didn’t sell as quickly as fresh corn.
For most customers this system put the cans out of reach.
The store owner or clerk needed a broomstick to reach up and topple the can of corn from the shelf and easily catch it by hand or in an apron.
And that’s where the phrase “can of corn” came from for an easy pop fly ball.