It's not about a tired pen, it's about how if you continually find yourself digging into the minors for a seventh or eighth reliever, you're not going to be calling up your best bullpen arms. In fact, a lot of the time you'll be calling up pure crap (Jeff Gray logged how many innings for the Twins?). In Burton, Fein, Perkins, Swarzak, Thielbar, and Duensing, the Twins have a solid bullpen core. That's six guys. Add in a guy like Pressley or Tonkin and you're probably looking at a pretty good pen if the starters aren't awful, forcing the Twins to reach back and call up pitchers who either aren't very good or aren't ready.