I think the main reason for the minor league thinness is that the Twins, for nearly a decade, squandered (or lost to injury*) their major league assets until they were bereft of value (Lohse, Valencia, Liriano etc.); those that retained their value became free agents (Cuddyer, Hunter). And the trades they did make just haven't panned out (Span, Revere, Santana). When the Twins crashed after 2010, they crashed suddenly and precipitously; leaving the team with little minor league or major league assets from which to rebuild. Competing in 2010, when the need to rebuild was probably foreseeable, may have been the worse thing for any possible quick turn-around. *Mauer, Morneau, Baker, Koskie, etc.