re: How big of a concern are lattimore's hammies, really

Arthritic shoulders don't heal. Hamstrings do.

Your bro-in-law is right on this one.

My buddy at work was the same as you, but didn't know about his shoulders. He was like oh damn.

For a guy that takes a pounding on those shoulders for a living it most definitely will bother him and likely shorten his career a great deal. That's a big part of why he "fell". Most teams were scared to touch him.