Not sure if it works in MLB 13 yet, but I do it in pretty much every sports game I own.
Do the draft but don't save, then afterwards just go and look at everyones ratings/potential. Reset the game loading up before the draft, and then draft the guys with good ratings. --- i7 2600K @ 4.6 Ghz | Gigabyte G1.Sniper 2 | MSi Twin Frozr III PE/OC Radeon HD 6950 @ 975 Mhz | 8GB Corsair Dominator | Corsair 850TX V2 | HAF-X Gaming Case
In the first few rounds, focus on guys who have been signed to big contracts already. So if you want a pitcher, go with Verlander. For position players, guys like Carlos Gonzalez, Miguel Cabrera and David Wright.
I say this because team budgets after a fantasy draft are determined by the total amount of salary you draft. So if you pick a bunch of youngsters on their rookie contracts (like Mike Trout, Bryce Harper, Paul Goldschmidt, etc.) your budget will be horrible. That will mean you won't be able to sign those guys when their contracts run out. --- "I am the last Claptrap in existence, and I AM GOING TO TEABAG YOUR CORPSE!" - Claptrap, Borderlands 2