How much value and potential do they have?
Duran has some value, although how much is in question. Mata is a bigger question mark right now, since he is not going to pitch for several months. Groome is finally showing something. Winckowski was traded a year ago as one of several players who only netted Andrew Benintendi in return. I don't expect his value has catapulted that much in the last 10 months.
Basically, after Duran, these are a bunch of question marks. At the deadline last July, teams were dealing ranked pitching prospects for half year to one and a half years of control. Are any of thee players part of any competitive offer? If I can foresee a fire sale in Oakland, it's a safe bet every pitching-starved GM with even a moderate budget also can. And the ones who can't will be getting told about by Dave Forst himself. Is Duran, Groome and Winckowski really a competitive offer?