Chuck, from what I understand (and I am very open to correction), Morgan didn’t really want a field command in the first place. He revealed this when he wrote his wife on 10 Sep 1863 that, “I never wanted the Coloncy of the regiment.”

This, combined with a political furor within his staff, the high degree of demoralization after Devil’s Backbone, and the black cloud that seemed to follow the 26th from the outset, possibly caused Morgan to re-evaluate his effectiveness. With this said, I think it possible that he didn’t “give up” so much as he wanted to get somewhere he could put his talents to work for the good of the cause without the barriers. His subsequent assignment with the Transportation Department was exemplary.