if you're training a G four levels in OD, for example, that's going to have a whole lot more of an effect than a random pop in SB and RB.
As I already explained in this or another thread today, I can't exactly remember: I'm training a Superstar guard for NT and for that, I have to keep his PA on Prolific (it's already on that level). If in three seasons of training he pops just once in PA, he can't play for NT anymore. If I knew this two seasons ago when I drafted him, I would:
a) sell him, improve my team and promote one season earlier
b) sell him and buy a MVP or HoF
Now if he pops in PA, I'm stuck with a player that will be good, but not good enough for NT and just above-average for D.I where I plan to be in 4-5 seasons. So what should I do? Sell him, buy myself a new 18y old and start anew, setting myself back two seasons? Or train him and risk a pop in PA, knowing this will kill all my plans with him?