Players position vs Players jersey number

What is the effect if a player say no. 4- 5 on his jersey plays as a number 2.....or a player say jersey no 6 -7 plays in the number 2 slot....and yes for that matter visa versa..... Further if one buys 6-7 player but puts him in a number 2 slot.....Still further if i change his number to the slot I want him to play in does it make a difference.
no effect whats so ever, except when selling him later in auction house, the only thing that matters is how the training points are allocated, ie if you are playing him at hooker he needs good passing skills for lineout throws but lineout jumping or lifting skills are wasted
This can be tested.