The skill
The player's skill is the most important factor of all. It determines how well a player performs in matches. Form can strengthen or weaken skill and that must of course be taken into consideration when selecting your team. The skill level you see represented by a number of "skill boxes" is not the player's exact skill. For example if a player has 6 skill boxes, his/her true skill is somewhere between 5,50 and 6,50. You will however never see the player's true skill, it takes a good manager to get to know the players well enough to be able to make good estimates about their true skill.

The player's skill level stays virtually the same during the whole season and changes only at season updates. It is then the player's development value during the season that decides if the skill level is raised or lowered. Read more about this in the form section.

The skill level has no upper limit. Though in reality there are of course limits on how good a player can get before he/she becomes too old.