Hard to say what Ward is? Even pre-surgery, he seemed to get bye in spite of his high bb rate. SoxProspects liked him, but were unsure how his stuff would play at higher levels.
Walter should be a fair back end of the rotation guy, but coming the injury is a question mark. Always old for his level, but did well in AA.
Murphy is probably just a reliever, I'll give you that. They may give him a few spot starts.
Mata should be the best out of this bunch. I think he'd be a lights out late inning guy if he scrapped one of his offspeed pitches.