The article goes into how this is more than simple "emergency" prep which the Brewers routinely do with multiple players. What the article doesn't go into is what would trigger the move to the IF. A trade opening up an IF need? A trade opening up an IF need and the logical 1st option falters? Or a dream scenario where all of Yelich, Chourio, Mitchell, Frelick, and Wiemer all not only produce and stay healthy, but all perform so well that they need a solution as to how to get all 5 in the everyday lineup. Could be as simple as that somewhat hopeful and slim scenario. That's a lot of lucky health and achieved potential though.
Finally it could all be about building trade leverage by demonstrating they have places to put this glut of OFs and thus don't need to sell any of them at a discount due to a perceived logjam. Honestly, this would be my guess.