As to the subject of this thread, It's a head-scratcher. More variables than you usually see when moving toward the trade deadline. Some random thoughts:
Someone mentioned Black possibly becoming a versatile piece---2B, 3B, OF. This could solve a lot of issues, but IMO the chances of that are zero. He looked OK yesterday, but there isn't even sufficient evidence he can reasonably handle 1B.
I think they're committed to Hoskins at 1B. Even if he heated up enough that someone would be interested there's no way they're finishing up the season w/two LHH 1B. And a team wanting him is contending & therefore not parting with a starter.
I look at Frelick, Mitchell, Black & Perkins and think the team would LOVE for someone to have a particular interest in one of them, if it would help assemble a package for a starter w/more than rental status. As always (it seems) the key is Mitchell. His health issues probably hamstring his trade value, and if a trade leaves him w/a prominent role in the OF, can he stay on the field?
I hate the idea of adding to the bullpen. I'd much rather rely on a Clarke, Herget, or Yoho, one of the current IL guys, or Williams coming back effectively then spending prospect capital on someone not all that better.
And if an OF DOES get traded & you need to have someone move up in the pecking order to provide shuttle depth, get Isaac Collins on the 40-man. Switch-hitter, even splits, can play a little INF in a pinch. Might come in handy.