Shooting Guard: Jacob Evans, 2018
The Golden State Warriors absolutely wallopped the Cleveland Cavaliers in the 2018 NBA Finals. After absorbing 50 points from LeBron James in an overtime Game 1 win, the Warriors won the next three games to sweep their rivals and win the championship, their third in four seasons. Entering the NBA Draft a few days later, they had the 28th pick and were looking to inject win-now help into their aging rotation.
To that end, they used the pick on Cincinnati guard Jacob Evans. The 6'4" Evans played three seasons with the Bearcats, evolving into a versatile player who could defend, pass, shoot and score. He shot 37.7 percent from deep in college and was the rare collegian to average at least a steal and a block per game in his final season. He looked like the perfect archetype of a player who could step into a rotation role for the Warriors from day one.
Alas, that was not to be the case, as Evans proved wholly unable to keep up with the speed and athleticism of the NBA. He played 57 games in two seasons with the Warriors, with his career-high just 14 points. He was out of the league after two years. The Warriors tried to eschew upside for a player ready right away, but Evans as a fully-developed player wasn't an NBA player, so the Warriors were caught both ways.
If the Warriors wanted an older rookie on the team to help their backcourt, they would have been much better off drafting Jalen Brunson out of Villanova, who went five picks later to the Dallas Mavericks. In fact, the 2018 second roud was a cornucopia of players who have carved out long NBA careers: Jevon Carter, Devonte' Graham, Mitchell Robinson, Gary Trent Jr., Jarred Vanderbilt, Bruce Brown, De'Anthony Melton and Shake Milton all went in the second round. Any of those players would have been able to contribute to the Warriors over the next feew seasons, but instead they swung and missed on a "sure thing" and it cost them.
Honorable Mentions: Jiri Welsch went 16th overall in the 2002 NBA Draft and lasted just four incomplete seasons in the league; Larry Hennessy went 10th in 1953 and played just 74 total games in two seasons before retiring.