IMO the Mets don't have the balls to trade Syndergaard, but they do have Anthony Kay waiting in the minors, a lefty who was their 1st round pick in 2016 who is 24 and absolutely dominated AA this year (1.49 ERA in 66 innings). He has struggled so far in AAA and the Mets have a bad situation to break in new pitchers with their horrible team defense, but he could fill in one spot at least. I do think they'll at least deal Wheeler and call up Kay, maybe Vargas too but not Syndergaard or Matz.
It is astonishing to step back and look at how well the Mets have done at developing starting pitching, the rarest commodity in the game, over the dozen years or so, and how mediocre they still are.
I mean, not all of these guys are great, but this run represents really impressive work by their player development people:
Mike Pelfrey (2006 debut; 12 year career)
Jon Niese (2008 debut; 9 year career)
Dillon Gee (2010 debut; 8 year career)
Matt Harvey (2012 debut; 7 seasons so far)
Zack Wheeler (2013 debut; 5 seasons so far)
Jacob deGrom (2014 debut; 6 seasons so far)
Noah Syndergaard (2015 debut; 5 seasons so far)
Steven Matz (2015 debut; 5 seasons so far)
Robert Gsellman (2016 debut; 4 seasons so far)
Seth Lugo (2016 debut; 4 seasons so far)
It really does feel as though with replacement level ownership and management (and a bit better health from Wheeler and Harvey), they should have reached more than one World Series or had a season better than 90 wins at some point over this span, especially considering that the division they're in has not been reliably strong.