Probably Brett Jackson or Logan Watkins, simply because they're already on the 40 man. I know Sczcur's on the roster, but as well as he's done and as much as Brett's struggled, they'll likely give Brett at least one more crack at the big league level before passing him over, unless he's included in a trade between now and when that time comes. I really doubt that any starting pitching prospect is brought up anytime soon. Whether it's due tom injury or performance, Even if we trade 2 and shut down/DL 1-2 more to injury, we're likely to replace them with filler like Raley, Rusin, or Struck rather than roster someone else. If you mean simply between minor league levels, I'm going to go with Rock Shoulders. Not only is he crushing the ball, but taking plenty of walks as well. Also, Tennessee really has no meaningful 1st baseman.