Definitely not the move I would have made, but I see the reasoning behind it.
Pros:
Gausman potentially gets 2 starts on long rest, and his heater usually pops after a break.
Yesavage available for Game 7 (and maybe Game 6) out of the pen instead of Gausman which is probably more of a weapon
Surprise factor to the Dodgers prep the night before Game 1
Cons:
Starting Yesavage for a potential Game 5 in on the during the World Series with those LA fans is asking a lot, even for a poised young man. This isn't like pitching on the road against Tampa in a little league park.
As of today Gausman is still our best SP, a handful of starts doesn't change that. If we get ran through in 5 games, we risk leaving him on the shelf without using him twice.
Again, not the move I would make, but I love the balls the front office is showing here.