Will there be a way when the new ranked system comes out that we'll be able to say that I am the role the game believed I am? I'm sort of annoyed seeing my games all of a sudden getting compared to the enemy ADC and not giving me any decent information. Just a question/thought.
..... wait. What?
I believe the system will determine your position based off of what you got placed as in champ select.
I think the technical position is called 'Bot' so if you played as Bot, the system will assign that role in your stats page. It doesn't matter was champion you pick (you can play adc, mage, support, tank anything basically, and it will still call you Bot).
If you did queue as support, then there might be something wrong with the system. You can send a Bug report to RIot about this.
