New players arrive with their current level of skill (actuals) and the projected level of their maximum skill (potentials). Just as in real life, some players do not reach their full potential in all ratings, while others may exceed those initial expectations.
The path of a player's development each year is based on multiple factors:
Players develop and decline in similar patterns. Some skills (like Speed) tend to peak early, while other skills (like Specialty) tend to take longer to develop. A player's development, peak, and decline ratings can modify that pattern - by speeding up or slowing down the rate of development, by shifting peak years earlier or later than average, and by speeding up or slowing down the rate of decline.
Reach peak development between 26-29yo.
Develop to their potential in 75% of their ratings.
Remain at their peak 4-6 years.
In addition to a player's overall tendencies, players have rating-specific development, peak, decline tendencies, which effectively make it so any type of career is possible. On the whole, ratings will still develop in predictable patterns, but on a case-by-case basis, one rating may peak earlier/later than expected, or one rating my develop more/less than the others.
At the start of each preseason, players in Low Minors get a small bonus to development of each rating. That boost is reduced when a rating gets to the league average, thus, players that need the most development will benefit from the Low Minors the most.
NOTE - once a player plays in a game, he cannot go back to Low Minors. If you wish to move a player that hasn't played from AAA to LMs, please contact your commissioner.