Think of the squad planner as the manager's private notebook, a simple management tool, in which he or she plans the depth chart for each position this season and in coming seasons.
The player's agreed playing time is what you seem to be referring to. This playing time promise is agreed upon when you sign a player's contract, but can also be changed in the player's profile. Agreed playing times include "impact sub", "fringe player", "squad player", "regular starter", et cetera. This is what the player (and their agent and your staff) understands the player's promised place in the team to be.