Players cannot leave for 7 seasons IF you bring them up after 20 games. And, quite frankly, I don't think I've ran across a player who wouldn't sign a long-term deal during his 2nd arb so you can make that 11-12 seasons.. So, really, I'd say you pretty much get their prime seasons no matter what. The only "real" decision is how much you're willing to pay for them.
Nonetheless, bringing up a 2nd year pro does not, in any way, shape or form, crush long-term hopes and dreams.