Hi,
black: 1-4
blue: 5-9
yellow: 10-14
green: 15-20

This is a bit easy to read a player skills.


Red is a different. Certain skills (speed, strength and agility) are limited by BMI. A heavy player will be limited in speed and agility, a skinny player will be limited in strength. When the skill is trained higher than the BMI limit, it will turn red. If you hover over it, you can see how high the skill actually is in matches. E.g. you have a player with speed 17, but he has 40 BMI. Then he will play with a speed of 16. You can lower his weight in the nutrition center in order to unlock 17 speed.