The Twins are probably relying on a bunch of obp coming from players already on the roster.
Buxton's 2017 started so impossibly bad but he hit .274/.335/.448 from the end of April on. That would be a big improvement over last year's CFers who posted a .293 OBP.
Twins are probably hoping that Sano gets back to the .350 OBP guy he was his first three years with us.
Kepler has pretty good walk rates (and power, too) but his babip is criminally low. If he can get his babip closer to .300, his OBP will look pretty respectable.
But, realistically, the Twins are building the offense around these guys and these guys need to step up, like Polanco and Rosario have. They can make some moves around the margins but unless they are going to spend more than the Pohlad's have ever indicated before, the significant change is going to be with those three guys.
Also, I think we should sign Cruz to DH.