Form box selection based on previous box selection?

I would appreciate help in doing the following for a form for people to select answers from - using Football as an example: (I am familiar with Lists but not how to make two different lists stay associated with one another.)
I have an Excel spreadsheet with one tab showing all the Football teams. Then there is a separate tab for each football team showing the names of all of its players.
I am trying to design a form where a person makes selections from two different boxes with drop down lists.
The first box shows a list where they pick their favorite football team. Based on that, the second would show a drop down list of all the players for that particular team where they would select one.
The results on the form would show the first box with a team name, and the second box with a player's name on that team.
How do I make the second box drop-down list show just those players for the team they selected in the first box?
Thanks for any help you can give.

Excel Box Selection