1. Noah Vonleh, 2015-16
Noah Vonleh was the No. 9 overall pick in the 2014 NBA Draft out of Indiana. Selected by the Hornets, Vonleh only spent one year in Charlotte before coming over to Portland in what was a horrible trade in retrospect. The Blazers sent Nic Batum in exchange for Gerald Henderson and Vonleh.
The Blazers were clearly high on Vonleh but were banking on his development and untapped potential since he only played 10.4 minutes per game during his rookie season. But it was more of the same for Vonleh and the Blazers in his 2015-16 sophomore campaign. Despite starting 56 games, Vonleh didn't show much progression, only averaging 3.6 points and 3.9 rebounds per game.
To make matters worse, this was a pivotal time in the Damian Lillard era, as the Blazers were just coming off of back-to-back 50-win seasons. There were plenty of other mishaps that happened in the Lillard era that led to his eventual trade request, but getting rid of Batum and taking a flier on an unproven Vonleh doesn't seem to be talked about enough. Vonleh never reached his ceiling in the NBA and is currently playing for the Shanghai Sharks in China despite being only 28 years old.