Deolis Guerra, RHP
At the time of the Johan Santana trade, Guerra was a soon-to-be 19-year old who had good stuff but had posted some pretty mediocre numbers as a starting pitcher in the lower echelons of the Mets' farm system. Over the next few years not much really changed...until he was shifted to the bullpen. His strikeout rates have risen significantly, with nearly one in four plate appearances ending in a strikeout in Triple-A in 2012.
For a guy whose pitches haven't developed as the Twins hoped they would, this change has rejuvenated Guerra's chances of becoming a Major League player. The relative depth in the bullpen currently means that the front office has the luxury of giving him a little more time in Triple-A this season, but it wouldn't be surprising to see him make his Major League debut sometime this summer.
Guerra still needs to work on his command in order to get the most out of his stuff, but if he can do that there's some potential upside still remaining. For right now, though, it's almost a guarantee that he'll start the season at Triple-A.
Fun fact: If you Google "Deolis Guerra scouting report", your related searches at the bottom of the page are "Kevin Mulvey scouting report", "Philip Humber scouting report", and "Carlos Gomez scouting report".
Chances of making the team: Unlikely.