Add a Title"You're garantueed one of your positions because you recently filled or played support"

I played like 6-7 games with thresh , and i got little bit exhaust from playing him so wanted to play a little Zed, and i picked Mid as my Primary role, but then I got filled as a Support again, I saw the message "You're garantueed one of your positions because you recently filled or played support" Where is my Mid lane ? It's annoying as fuck when you play support all damn time and once you want to change your position and still get support, its not that i like it but its not garantueed , bs.