I read somewhere that if we had traded for Johan Santana and Masterson was involved then the Twins would let Joe Nathan walk and Masterson would become there closer of the future.
Honestly I want him in the rotation long term. He is a sinkerball pitcher with the ability to strikeout hitters. He has the best sinker in all the minors and could spark a debate in the majors (Brandon Webb and Wang are tough to beat though). When rosters expand and the minors season concludes then I would let Masterson contribute in the pen. His future to me though is in the rotation. Think of the young guns and how they are all different...Masterson a sinkerball pitcher, Lester a crafty lefty, Bowden a control pitcher, and Buchholz just flat out nasty. Trade someone for a great bat to replace Manny later in the future.