Yep. Cycling through DFA claims is how you get the Twins pen.
Also, the :just convert some starters" line we see trotted out sounds fine but it's hard to pull off and certainly can't be done in an offseason. Nobody has enough spare starters sitting around in the high minors with the kind of stuff needed to really be a difference maker to throw a half dozen at the issue. You might find one or two per year.
Bullpens need to be built, with quality, over time.