Players that are created in season 13 or later will have a training morale parameter. This is an indication of how much a player is learning from his training in that season. A higher training morale means the player will get more experience. We'll explain this below in more detail.
The training morale is a small hidden part of the talent and a hidden bonus/penalty on how much experience a player gets from matches. Depending on the training morale, a player can have 0.5 ball talent more or less (or anything in between) than what is shown. He can also get -10% to +10% experience for every match he plays.
Both the talent and the match experience part are composed of two parts. One part is fixed for the player and the other part is randomly decided each season. This means that the training morale can be different each season, but some players will have on average better morale than others. The average values are most common. Very high or very low training morales will be rare.
The training morale is shown as a text, followed by a number. For example "Above average (+1)". This is a combination of the talent and the match experience part. It's possible that the talent part is very high and the match experience rather low, or the other way around. They can also both be a little above the average. The number "+1" has no meaning, except to say that it is better than average (0) and worse than +2.
Training morale has no influence on how a player performs in matches, only on how much experience the player receives in that season.
The training morale of all players is reset in week 2 of every season. When a player is created or promoted from the youth center, his morale is always average until the next morale reset.