In my mind "Core" guys are those you are thinking could likely retire with the team. At this definition, I doubt any of these guys are core. But for a longer term player: Nelson - he has always been a bit of a tease to be dominant with control being his biggest bugaboo, but I think last year's loss of control was a fluke; a worst case outlier. This year is interesting to me because he has changed that way he pitched. For years he was forced to be a lowball pitcher. And now he moved up to a high-ball pitcher. As long as he controls his curveball, he will be effective (same with Anderson and Knebel there). Finally, as a pitcher, we need to take a chance that it is legit. Shaw - The simple reason for him to be considered core is we don't have a replacement. Erceg might be, but is a few years away at this point. His MiLB numbers and scouting back up that he is a legit MLB bat. Maybe not a 900+ bat, but certainly a 750-850 type hitter. With no one to push him out, what other choice do we have? If Erceg starts knocking on the door, then you evaluate how long he stays or if he is trade bait. Santana - I think he is probably the most "legit" of the three. Ironically, he is also the most replaceable with other prospects knocking at the door.