That's a good question. Vierling? Or maybe Jake, but Vierling would have better reach. Plus you get the impression McKinstry can field any position at least adequately but again - no reach.
And I'm sure a big reason they give Torkelson so few days off is that Javy is really terrible throwing to 1st. Seeing the way he throws, you realize that if he hadn't had Rizzo at 1st on the Cubs he probably couldn't have stayed in the majors at SS. And now he has lucked into Tork to save his bacon.