Also, there is no track record of a catcher with Kirk's build, so there will always be a fear that he might have to give up catching at some point.
I suspect he'll end up at DH. Not that I'm saying he shouldn't be a catcher, I like him a lot and would love to keep him, but this team is in the interesting position where it has plenty of up and coming young offense. He's not really needed, and they have greater concerns elsewhere (like the entire outfield potentially being gone in 2 years, for example), plus his footspeed is potentially a major problem. He's starting out his career, at a very young age, super slow. He's only going to get slower.
I hope someone teaches him how to run. I was equally slow as molasses when I was younger until a track runner taught me how to run. Improved all the way to average speed.