Cashner was one run away from a quality start. Mancini pretty much ruined the day for him. However, he did pitch a lot better than overpriced Porcello.
Well, there's the slight chance that some GM of a non-contending team may, as someone here already mentioned, value Beni, believing a change of scenery might prove beneficial.
A package of Beni and JD might garner a decent starter. However, JD's opt out clause may cause some AL teams to hesitate. He might be attractive as a rental for a contending team, but what contending team is going to give up a decent starter?
The SOX are not going to get a 'top shelf' pitcher for Beni alone. He'd have to be packaged with someone else and cash. Every game Beni plays his value decreases.