2. James Ennis III
After seeing Trevor Ariza ink a one-year $15 million deal with the Phoenix Suns, the Rockets sought a replacement for the 3-and-D vet. Although Rockets' fans' final memory of Ariza in Rockets Red was the NBA champion going 0-for-12 and 0-for-9 from deep, his role was quite pivotal.
Ariza was able to anchor down on the opposing team's best offensive threat, which was far more valuable than anything he did or didn't provide on the offensive end. The Rockets thought James Ennis would be able to replicate Ariza, at a fraction of the cost.
Rockets coach Mike D'Antoni spent all offseason trying to convince himself that the team would be better defensively, despite losing an All-League caliber defender.
Needless to say, the defense wasn't better with Ennis. And Ennis wasn't good at all. It only took the Rockets 40 games to end the experiment, as the team dealt him to the Philadelphia 76ers. Ennis averaged 7.4 points, 2.9 rebounds, while being food for opponents on the defensive end.
In fact, former Rockets guard and future Hall of Famer Chris Paul stated that the loss of Ariza led to the downfall of the team, which he wouldn't have said if Ennis had successfully supplanted Ariza.