Back in OOTP14, my first OOTP, I was playing from the MLB Quickstart as Houston. Left fielder Jose Marmolejos-Diaz was minor-league filler in the low minors for the Nationals. They released him, and my Assistant GM or whoever signed him to a minor league deal. He then went on to become a star for the Astros, a really phenomenal hitter, with an OPS over .900 for years. It was really random but really fun.
I'm now playing as Tampa Bay in OOTP16. Jose Marmolejos-Diaz started my playthrough as, again, minor-league filler. Now in 2017 he is the top prospect in the game. I looked in the editor, he really does have some insane potential ratings now. He doesn't even have a particularly high work ethic, and he's not particularly smart. But he looks like a lock to be at least a star, maybe even a superstar.
So, here's the lesson for everyone: the first thing you should do in every game is get Jose Marmolejos-Diaz from the Nationals