Modifying a sandwich bread recipe?

Toast

http://www.thekitchn.com/how-to-make-basic-white-sandwich-bread-cooking-lessons-from-the-kitchn-166588

I've been making this recipe for sandwich bread consistently for the past couple weeks, and I really enjoy it, but I'm wondering if I can just switch out the butter for olive oil instead. I'm assuming the butter is to help keep the loaves soft?