Stay with me here.
Besides David Wright and Matt Harvey (and recently Bobby Parnell), the only other real sure thing we have is Daniel Murphy. He will hit at minimum .290 with a reasonable amount of extra-base hits (49 last year was above players like Paul Konerko and Derek Jeter so I'm pretty sure that's above average). He's on pace this year for 56 extra-base hits with a batting average currently twenty points lower than his career numbers (he could bounce back to career norms and end up with 60 extra-base hits). He plays passable and at times above average defense at second base with a hard-nosed and gritty approach to the game. He's someone the fans rally around and he's the clubhouse leader behind David Wright. This is the kind of guy you win ballgames with.
The flipside is that Wilmer Flores is hitting above .300 at AAA at the ripe age of 21. He has shown the ability to play passable defense at 3B, 2B, and 1B. Though he has all of the promise in the world, I'd speculate that his ceiling is probably .310 with about 70 extra-base hits. I'd speculate that his floor is probably .265 with about 50 extra-base hits. Obviously, this is not an expert opinion, but it seems that he will fall somewhere between that, which is close to Murph's value. However, I believe that we can sell Wilmer Flores based on his pedigree and his ceiling in order to get a player in return who will not be a "fish out of water" at their position.
If it came down to making the center-piece of a deal Montero, Syndergaard, Fulmer, or Flores, I believe that including Flores in a deal makes the most sense for the Mets. Daniel Murphy is a sure thing, Wilmer Flores is a wild card. Let's sell high and pick up a legitimate outfielder. I'm not saying Wilmer Flores is enough to get CarGo or Stanton, but he's certainly an enticing part of any offer we might make, bearing in mind that both Rockies and Marlins have openings at 3B.