No, you won’t get in trouble. Niantic has stated that for sports courts, fields, etc, they should be placed where the games do not take place, such as on the side of the court or field.
Baseball and softball fields are good examples, as a good location for them is at the backstop fencing. This location can still be accessed by someone watching the game, without interfering with the game. Here’s the info from the sports field clarification: