9. Derrick Jones Jr.
One of the best veteran's minimum signings in the entire NBA was when the Dallas Mavericks signed Derrick Jones Jr. to a one-year deal. This signing happened pretty late into the offseason, but Jones Jr. has quickly outplayed that contract and turned into a crucial piece for this Dallas team.
Throughout training camp, people expected Josh Green to be the starting wing. He had just signed a three-year extension, and people thought that he was ready to take the next step in his career.
Then rumors started to fly that Jones Jr. could be someone who could end up being a starter.
After over a quarter of the season, Jones Jr. has started in every game he's played in and is playing the best basketball of his career. He is averaging 9.8 points, 3.6 rebounds, 1.0 assists, 0.8 steals, and 0.8 blocks per game while shooting a career-high 35.5 percent from downtown.
He is finally playing for a team that gives him the green light from downtown, and playing with Luka Doncic has helped him turn into an elite 3-and-D threat.
With Jones Jr.'s high level of play and expiring contract, I don't see many scenarios in which the Mavs trade him. Considering how well Dallas is playing, it wouldn't make much sense for them to deal a player who has been vital to their success.