Tough question, because the pool of players you're looking at is diverse. When looking at a prospect, I'd say he'd need pretty good minor league offensive numbers. Nothing outstanding, even for the position, but numbers that would probably net them a starting role if they repeat them in the bigs. Mike Fontenot(.272/.377/.430 at Iowa last year), although he doesn't play shortstop, is a decent example of such a player, although even someone with say a .350/.400(OBP/SLG) would work depending on their full body of work(physical tools, fielding ability, full minor league history). In the case of a more journeyman type player, Neifi sets an appropriate baseline, as very few players find themselves on base as little as he does. Again, not to say blindly dump Neifi for a guy that has similar numbers but is a couple years younger, the other factors previously mentioned play a role. Also, for the record, I advocated going after Furcal/Lugo/etc this offseason, because I wanted Cedeno in Neifi's role this year. That gets Cedeno more major league time and he is still able to help the big league club, then he either moves to 2B(if you get Furcal and Walker departs to FA) or takes the full time SS role(Lugo leaves for FA). It also keeps dead weight like Neifi off the club. But the Cubs are stuck with Neifi, and the rest of the nightmarish moves Hendry made this offseason, so I guess I can dream that Neifi goes crazy and gets himself moved.