Is there an American sport league that limits the number of foreign players?

Yes, Major League Soccer (MLS) has regulations that limit the number of foreign players on each team's roster. Teams are allowed a certain number of international slots, which can be traded or acquired, but must also maintain a certain number of domestic players. This framework helps promote American talent while still allowing for international competition. Other leagues, like the NBA and MLB, have different approaches but do not impose strict limits on foreign players.