4. Kevin Martin (2013-2016)
Joining the Timberwolves from the Oklahoma City Thunder in 2013, Kevin Martin quickly became a reliable starter in the 2013-14 season. At 30 years old, he was still a solid contributor and finished the year second in points per game average, behind only Kevin Love.
The next season, Martin still put up solid numbers but had to miss extended time due to a right wrist fracture. As a result, he ended up only playing only 39 games for the Timberwolves in the 2014-15 season.
With Martin’s age beginning to show, Minnesota would have been smart to find a good trade partner and ship him out while they would have still been able to get some reasonable assets back from him. But instead, they kept him around through the next season.
Martin again played just 39 games in the 2015-16 season, and the team would reach a buyout agreement with him in March 2016. From there, he signed with the San Antonio Spurs and played just 16 more games to close out his NBA career.
After retiring at just 32 years old, it is clear the shooting wing did not have nearly as much left in the tank as the Timberwolves thought he did. As a result of not getting rid of Kevin Martin earlier, they lost out on the opportunity to get anything of worth back from the aging role player.