Yes, I am sure

Well it can happen that you don't have an ideal player for all possible positions your players are placed in a match. For example if you don't have any AMR in the bench and your AMR player gets injured, Top Eleven will select the player that can perform better in that position from the list of substitutes. It could pick an AMC (if you have it) for example. It picks the better of the available ones (not the better in terms of quality, the better in terms of position).