Lots of freshmen get down when they are not immediate stars. Sports Illustrated feature on Derrick Henry said he was really unhappy as a freshman as well. Seemed to have turned his career around though. Happened to a lot of my friends' kids as well, none of whom are athletes, it is a big adjustment from HS to college, no matter who you are.
The above disclaimer aside, I would not be surprised if the OP is true. The whole Harris recruitment, coupled with the surprise announcement (to most of us anyway) to sign with Alabama, where PLENTY of highly touted RBs have been buried on the depth chart, just screamed "Bad Decision" to me. I don't hold any ill will towards him, if he wanted to come to UK, great, if not, I think the sun will rise again tomorrow anyway.