Since we've still got about 24 hours before the next game, here's a bit of meaningless speculation on another scenario at the deadline: Madison Baumgarner.
The Giants have to sell him, and he should get a decent return, but I also doubt that current day GMs are going to overpay for his previous MLB playoff dominance. A good ballpark for value that people are pointing to is the Yu Darvish deal, which sent a top-100 prospect in Willie Calhoun and two other top-30 prospects in a deep Dodgers system.
Three guys is a lot for a rental, but one thing that might help the Pirates out in this kind of a situation is that they have a relatively deep system that is stocked with interesting players. For good reason, I'd imagine Huntington will be gunshy to offer up Hayes, Tucker, or Keller, and although I've repeatedly spoke in favor of moving Keller if it lands Stroman, Huntington probably has the right inclination there if I'm true.
But a true rental situation where you are parting more with depth options might be the ideal kind of package for us to think about, especially since we have some good depth at infield and outfield in the system, including at the very top now with Reynolds, Tucker, Newman, and you can throw Polanco in there as well because of his contract (and even sort of his age).
What does this mean, concretely? Well, we were just lamenting Swaggerty's numbers this year, but he's a prospect that has a similar top-100 profile as Calhoun, or you could take a guess and say he'll drift off the next list, but Craig will have worked his way on. I think there's also some chance that Calvin Mitchell will work his way on. So perhaps one of those guys is the starting point for a MadBum trade, and then the two supplemental pieces could come from the group of Kramer, Alemais, Oliva, Martin (Mason or Jason), Sanchez, or perhaps one of the prep arms. And maybe you even include a guy like Juan Pie as the third piece, instead of one of those other options. It would certainly be a lot to give up for just one rental, but it would be hurting our system more in terms of depth than anything in the near-future window of 3-5 years. Continued solid drafting could replenish that depth fairly well, and as long as you are a believer in the guys like Reynolds and Newman who have broken out, then it's a classic in terms of an aggressive move that doesn't break the bank.
All that said, my hunch is that the team that gets him might end up being the Braves, Brewers, or Astros, because those teams all have the kind of pitching prospect that you might want headlining a deal, whereas Keller is a little bit better than what I'd want to see us do. However, a final twist in this idea is that it gives the Giants more control about getting three pieces that they'd really like, since Bumgarner has basically put all of the other teams who would feasibly try and get him on a no-trade list.