The Pirates situation is still such a mess (more below), but I thought this proposal from a Red Sox fan for Duran was somewhat of an interesting temperature check. It's three solid but not spectacular prospects, the kind of trade that a team with a solid system can certainly match.
The standard Red Sox fan resistance seems to be that they want controllable pitching or a 1B solution in return, but the realistic Red Sox fan gets that any contending team is not going to deal that kind of talent at the deadline.
Were the Pirates actually interested, I think that could make a Keller swap advantageous, but like we said before, trading Keller for MLB talent would be a significant step backwards for an MLB team that already isn't good enough. The one angle I could see is financial, but 1) the Pirates likely wouldn't reinvest it asap, and 2) it would not really be possible to reinvest it in a player like Keller either.
I think the SP depth is too thin unless you are someone who really believes Duran can get back to his all star ceiling, which I'm skeptical about. The only way to squint and see it would be as a kind of shifting of the window (again...) in the sense that money could be reallocated to guarantee some cost stability with Skenes and/or Cruz, but I can't see it with either.
It's definitely not worth entertaining much in terms of a Pirates prospect package that could potentially work, since getting him is a kind of pipe dream anyways. The only other buy low OF option I see out there is Luis Robert, but the situation with the team is so cloudy that I just don't know what the real outlook is for us. Reynolds maybe going sideways is something that really looms badly, since any path to immediate contention in the next 2-3 years will require at least something from him.
Maybe Ashcraft or Mlodzinski show enough in the next few weeks that they can be part of a prospect package that would net this kind of return (no idea about Duran specifically, but I think that's part of the hope of the FO), but that seems like a long shot too.