There is still plenty of time to go before Opening Day, but my bet is still on Seratelli. Flores has options and may benefit from regular playing time at shortstop and second in Triple-A.
To me, either Flores starts in Citi Field or Vegas. It's a waste of time to let him play sporadically in any location. Omar Quintanilla has proven time and again that he has no business being anyone's top choice for a 25-man roster.
I'd just as soon give a shot to Seratelli to see what he can do, while Wilmer gets reps in Vegas, Ruben Tejada starts at short, and Sandy Alderson continues to work to trade for M's SS Nick Franklin or sign free-agent SS Stephen Drew.