This article from NFL.com suggests Barkley’s stock did not drop because he would not have been drafted that high last year anyway.
“I don’t think Barkley really hurt himself,” an AFC college scouting director said. “He was the same guy last year. He didn’t start falling in October, no matter where he was on everyone’s ‘big board’ in December. I looked at Barkley (after his junior year) and I thought he was a backup quarterback. I told people, ‘I’m not sold.’ And it was the same thing this year. In the end, I don’t think he hurt himself.”