The Oakland A’s need pitching depth. Right now their rotation consists of Mike Fiers, then a few out-of-options swingmen, then a couple top prospects who have barely pitched at Triple-A if at all, and then a bunch of guys who will return from injuries at various points in the spring and summer. There are some names, but not a whole lot of certainty about most of them.

It sure doesn’t look like any big additions are coming this winter, and even another cheap innings-eater or bounce-back candidate wouldn’t solve everything. And even when they do put together their best five arms, we’ve seen the toll injuries can take over the course of a summer.

That means they need depth, and lots of it. They need to maximize their pool of auditions this spring to increase the chances of finding some keepers, and they need to make sure there far more than five starters still available once the season starts. Not everyone can satisfy both criteria, though — for example, the recently claimed Parker Bridwell adds a name to the pile, but he’s out of options so he doesn’t really add to the long-term depth. He’ll either beat out one of the other out-of-options guys (Mengden, Montas, Bassitt), or he’ll have to be waived anew by the end of spring.

With the packed roster, there’s only so much space to add more flyers like Bridwell or Tanner Anderson. However, there is another way to add depth, and that is minor league free agency. The A’s made full use of this just last spring, inking Brett Anderson to a non-roster contract that allowed them to wait until they needed him in May before rostering and promoting him. In June, they did it again with Edwin Jackson. If using a taxi squad of optionable relievers is a loophole to functionally expand your 25-man roster, then finding legit MLB-caliber pitching depth on minor league deals is a way to essentially expand your 40-man.