{% set queryparam = '&sport_filter__in=' ~ module.sport_type ~ '&limit=3' %}
{% set case_data = hubdb_table_rows(module.hubdbtable_field, queryparam) %}
Where module.sport_type is the id of your selection field. Use capitalize filter e.g. "module.sport_type|capitalize" if you're not ensuring the values of the selection field are written in sentence case so they match the values from your HubDB.
{% set queryparam = '&sport_filter__in=' ~ module.sport_type ~ '&limit=3' %}
{% set case_data = hubdb_table_rows(module.hubdbtable_field, queryparam) %}
Where module.sport_type is the id of your selection field. Use capitalize filter e.g. "module.sport_type|capitalize" if you're not ensuring the values of the selection field are written in sentence case so they match the values from your HubDB.
You have to match your HubL output with the HubDB values. So if all your values are first letter capitalised only e.g. "Athletics" or "High jump" (sentence case), then do
module.sport_type|capitalize
Depends how you've written your values in the HubDB.
Just match the values of the choice field in your custom module to the values in the HubDB, so specifically set the value to be "AFL" and it should work.