I don't know where to put this, but for minor league bats, I'm excited about Matt Antonelli and Rick Hague and Jason Martinson this year.
Antonelli could be a big time bounce back from injury. His blog - http://www.matthewantonelli.com/
- is outstanding. He seems like such a good guy and an easy guy to root for. His recent post on free agency was outstanding. Former first round pick of the Padres, I think he and Corey Brown could both see some time in the bigs this year.
Hague was just raking last year at age 21. He should only get better. I think they try him in the outfield - it's fairly common for SS's to convert to outfielders, often CF, if they can't hack it in the infield. His bat, though, is promising.
Martinson, at least from his one minor league season, looks like Lombardozzi - a scrapper who just gets on base. If he can continue doing that, he'll be successful here. We're going to have plenty of mashers between Werth, Zim, and Harper. We're going to need guys who can get on base.
Kevin Keyes was pretty terrible last year, but the tools are there, anyway. Looks like a guy that will hit a ton of homeruns in the minors, at a minimum. Maybe a future 1B? I doubt he sticks in the OF.
Another random thought - we don't have very many Latin American FA's outside of Maya and Frowney Gonzalez. Hopefully at some point, we see the new program in the Dominican start to pay dividends.