Everson Pereira
So Pereira might not have done enough to boost his trade value, but he also didn't do enough to solidfy himself as the Yankees' left fielder of the future. His underwhelming bat got 103 plate appearances (interrupted by an injury as a result of tripping down dugout steps) and he hit just .151 with a .427 OPS.
Nobody's asking for a .300 average and .900 OPS, but you simply can't do that and strike out 39% of the time. Not gonna fly.
Then again, something is wrong with the Yankees, outside of the otherworldly talents (like Gerrit Cole, Aaron Judge, Jasson Dominguez) who have immunity to whatever's plaguing the rest of the roster. Pereira is one of many prospects that have come up only to be stymied by MLB competition, further proving the Yankees have a development issue with their young talent.
Smarter teams out there, however, will take note of that and find value in Pereira. It might not be what the Yankees prefer in trade talks, but if it means they can include him in a package deal for something they need immediately, they shouldn't (and probably won't) hesitate to do so.