To me, in this context at least, 'upside' means potential to show lasting improvement, not have a better season than last year or career norms. Otherwise, what's the point of the discussion? One good year in AAA relief has very little value to the future of the franchise. So looking at your list in that regard, Guerrier is obviously off, and I would argue as jharaldson did that after last year's derailment and 8 years in the minors without earning a look in the majors, Guerra is too. Raley looks to me as if the Twins had lost Diamond in the Rule V and wanted to go out and get the next closest thing, so that's a no. Ibarra is a marginally better prospect than Raley, and probably makes the cut just because he's a lefty. Pressly barely makes it as well, primarily on the strength of a good 2013 despite weak peripherals. So basically half that group looks to me to have little to no upside relative to what Worley has done or even relative to the high end projection of a Worley converted to relief. Not everybody turns into Glen Perkins just by going to the pen, but it's not rare for failed starters to succeed in relief.