Clippard was considered a prospect, albeit a fringe one - #5 starter material. Lannan was never expected to make the majors, until right before he did. Ditto Stammen. Lombardozzi was projected as a backup who gets by on hard-nosed D alone. However you slice it, we definitely have more than 3 players who made or beat their projections as prospects.
Prior to the 2008 season, Baseball America ranked JZimm our #7 prospect, behind Balester, McGeary, and Smoker. He was projected to be a #5 starter in 2011 (and Ian Desmond was cited for his defense alone).