4. Dennis Smith Jr.
Dennis Smith Jr. was a fan favorite in Dallas but was included in the Kristaps Porzingis trade with the New York Knicks back in 2019 and has bounced around the league since.
Last season for the Charlotte Hornets, Smith Jr. averaged 8.8 points, 4.8 assists, and 1.4 steals per game. He had a massive comeback season and turned into one of the most underrated guard defenders in the NBA.
He has great hands, moves his feet well, and plays with great physicality and energy. The Mavericks would have benefitted from having him as their backup point guard, but they ended up signing Dante Exum to a two-year deal instead.
Exum will likely fill the same role that they would have asked of Smith Jr. and has better size than him as he is 6-foot-5 while Smith Jr. is only 6-foot-2. Exum also has better versatility on defense, but bringing Smith Jr. back would have been a great move, and the Mavs could have signed him for cheaper than the contract they gave Exum.
He would have run the second unit, been relied upon as a defensive stopper, and already has a great friendship with Luka Doncic. Smith Jr. ended up signing with the Brooklyn Nets on a one-year deal, and a Mavericks return could be possible later down the line even though there was no reported interest in him from Dallas' end.