Varland is a no brainer move into the closer role at this point.
He's made some type of adjustment that has thrown hitters off. The quality of contact he's giving up is way down (he has given up 0 barrels so far this year). Hard to say what it is but his fastball-sinker have exploded in value. His arm angle is down a bit but not enough to call it a new arm slot. Hitters are swinging way less, and making shit contact when they do swing. His swinging strike rate is actually down from last year (velo is the same...on his sinker it's actually down) so it's not like it's a tick up in his stuff either. It might be sequencing, or the change to arm angle has his FB-SI tunneling better, dunno.
When I have a bit more give a fuck I'll take a look at some of his data on savant to see if the shape of his pitches have changed at all (his FB ran flat last year). But regardless of the why, he's the obvious pick to take Hoffman's job.