Yes, there could be - players who are promised a starting spot (and then are not started) or promised a certain amount of playing time and do not get it could do any number of things ranging from nothing all the way up to quitting.
NOTE: For playing time promises, keep in mind that a player's Stamina greatly affects how much he can play, so promising 75% playing time to a player with mid to low Stamina may not be possible. It is recommended that you get a feel for how much Stamina affects playing time in the game before you start making promises for playing time.
Players expect to receive their promised starts and promised playing time in every game to avoid any repercussions, not just average it.