Philip Humber (elbow) will begin a rehab assignment with Triple-A Charlotte Sunday. Humber, who is nursing a right elbow flexor strain, isn't sure how many rehab starts he'll need. ''That's out of my pay grade now,'' Humber said. ''I don't really know. I'm just taking it one day at a time. [Trainer] Hermie [Schneider] is in charge in the training room.'' He seems likely to return by late July if all goes well.