6. Hedo Turkoglu
The name Hedo Turkoglu likely hasn't crossed your mind in a while, yet he is one of the few players the Spurs might regret letting go of too soon. His lone season in San Antonio saw him record the eighth-highest three-point percentage in the league, become a full-fledged starter, and perform well enough to sign a lucrative six-year $36.8M contract with the Magic in free agency during a famously frenetic 2004 offseason.
The Turkish youngster immediately blossomed with more opportunities on a rebuilding squad, taking home the Most Improved Player Award in 2008, garnering All-Star consideration, and helping Orlando make their first NBA Finals appearance in over a decade. He also forged a legacy as one of the original point forwards that ushered in the trend of positionless basketball that permeates every square inch of the modern era.
While San Antonio won a championship the year before and after his short tenure with the organization, there's a chance Turkoglu could have been a fourth musketeer to Tim Duncan, Tony Parker, and Manu Ginobili. With the advantage of hindsight, it is easy to blame the front office for letting Hedo walk for nothing. But there is no way to promise he would have developed into a reliable scorer and dynamic playmaker had he stayed in the 2-1-0.