This question is two-fold.
First, if you promise a recruit minutes / starting and you follow through with that promise, do recruits' ratings see any benefit? In the past, I always felt those are the recruits who tend to see increases in ratings (including WE), but this has always been a assumption of mine.
Second, due to this baseless belief, I promised a recruit 10 minutes thinking I may be able to increase his WE a little and he may eventually be a viable player. However, if he is not going to receive any benefit, he isn't good enough to play 10 minutes now. If I did not follow through with that promise, would I suffer any negatives other than potentially losing the player? Prestige, future promises, current players, etc. being affected? He isn't terrible for even the couple minutes per game, but I have a bench player who I'd prefer playing this season if I can.