We're talking about trading prospects here, be warned
If the Yankees are going to substantially improve their roster this season they're going to have to trade some of their prospects. I know, the team needs to get younger, blah blah blah, but also they need to get better and not every deal is going to be for Vidal Nuno. If the Yankees trade some of their youngsters, it'll be ok; there are always more.
When trying to evaluate what pieces the Yankees have, you should probably know that the Yankees don't really have any blue chip prospects at their disposal. They have four legitimate pieces in their system that teams looking to rebuild should be asking about, but everything else is just supporting cast.
Gary Sanchez might have been a blue chip at some point, but he hasn't lifted off as a can't-miss prospect and has fallen in his prospect ranking every year. Because of this, you can probably give up on the idea of acquiring David Price or anyone of that caliber, but many organizations would still like a chance at a catcher who can hit for power.
John Ryan Murphy is probably their best major league-ready prospect at the moment. A team like the Chicago White Sox, looking for some young upside behind the plate could make Murphy their No. 1 priority thanks to the indication that he's incredibly advanced with the glove at this point in his career. He's not exactly hitting well in Triple-A at the moment, but he showed he wasn't completely useless with a bat in the majors. If someone thinks they can build around him he might net a decent return.
Luis Severino might be the organization's top prospect at this point given his status as a top 50 prospect according to both Baseball Prospectus and Baseball America. He's very young for his level, but if the Yankees believe his delivery will ultimately push him to the bullpen, it might be a good idea to trade him while his value is on the rise.
Rob Refsnyder has been very exciting to follow over the last two seasons, however, in that time he hasn't gotten a ton of attention as far as prospect rankings are concerned. There are still serious doubts about his defense and that will ultimately determine the value of his bat. If a team believes he's for real or they can give him the time he needs, Brian Cashman could ride the hype Refsnyder is currently getting all the way toward a very solid return.
The organization has other tie-in pieces that could sway an organization to take a deal. Peter O`Brien has hit 28 home runs this season, but he really doesn't offer a whole lot more than that. Maybe Cashman can sell someone on his amazing power in order to get a piece that is more likely to help the big league club. Rafael De Paula is an intriguing pitcher who can strike batters out but has not had a lot of success since graduating to High-A Tampa. Many believe he'll end up as a reliever, but it would be smart to deal him before that determination is made. Once promising prospects like Mason Williams and Tyler Austin could be easy change-of-scenery candidates and a team might be interested in taking one and hoping they can turn him around.
The organization really doesn't have any prospects I wouldn't trade in the right deal. There are no must-keeps here, and with prospects being so overly valued right now, as we've seen with the Jeff Samardzija trade, it gives the Yankees a lot to work with. Sure, there are prospects I would like them not to trade: namely Aaron Judge and Luis Severino because they have the potential to blossom into more useful pieces in the future, as well as Greg Bird and Rob Refsnyder because I've really enjoyed following their careers to this point. After the crushing blow that was dealt to my heart when the Yankees traded away Jesus Montero a few years ago, I don't think I'll ever allow myself to get that caught up with a prospect again. Not only was Montero traded, but he completely failed afterwards. It taught me a valuable lesson–prospects break hearts–and I won't be done in like that again, no one should.
Do what you have to Yankees, make the team better if you can or hold firm if you can't, just do something smart. If you need to trade any of the prospects I've grown to love, I'll understand, unless it's a bad deal.