Jameis Winston
The Tampa Bay Buccaneers made Winston the first overall draft pick in 2015 and everything appeared to be rosy. He set franchise records in his first couple of seasons but then things became unsettled. Winston has phenomenal talent but no coach managed to manipulate it into the full package (via ESPN).

It didn’t help that he had three head coaches in his Tampa Bay career. Yet on the field he was a wild interception machine and there were serious problems off the field. He made the Pro Bowl in 2015 but never looked like replicating that. Then Bruce Arians sent him to New Orleans but he failed to show that he was Drew Brees’ long-term replacement.