When a player levels up in campaign mode, there is a dice roll (2d6) before you are allowed to choose skills and/or pick an attribute to increase. What is the purpose of that dice roll? What happens if I roll double 1s or double 6s?
Each skill is in one of five categories: Mutation, Strenght, General, Agility or Passing.
Also, if the total of the roll is high enough, you can in stead choose to raise one of the players attributes as follows
What ever the roll, you can only choose either one skill to gain or one attribute to raise.
For more information, see the Living Rulebook (page 40 deals with these rolls). The game follows these rules pretty faitfully, with some exceptions and Blitz mode spesific additions.