Regarding Maybin, it looks like he just had a small setback:
Jul 6 Maybin has been placed on the DL for Double-A Carolina with a muscular injury in his back, the South Florida Sun-Sentinel reports.
Recommendation: He hurt himself on a swing Thursday. The injury isn't thought to be too serious, but at the same time the Marlins began making inquiries about players like Wily Taveras and Scott Podsednik afterwards, an indication that perhaps Maybin was close to being called up before getting hurt.
Doesn't sound like he'll miss much time; if FLA is smart they won't rush him back.