Reca - Usually when this happens it is because you started a tournament and did not finish it for whatever reason.
The way to make this go away is to start another tournament (a free, unlimited entry one would be best) and then either play it through, or if you have to quit it, use the menu - quit and not the red X in the corner.
When you get back, the friends AVAILABLE TO: should reset to where you want it.
Hope this helps.
Ciao!