8. Royce O'Neale
The Brooklyn Nets have received "a number of calls" for Royce O'Neale, and the Mavs making a move for him would be massive.
Just like the previously mentioned Alex Caruso, O'Neale would give Dallas an elite defender. Standing at 6-foot-6 with a sturdy frame, O'Neale could plug in as Dallas' starting wing next to Luka Doncic and Kyrie Irving.
He would be one of the best defenders on the team immediately, and his shotmaking ability would flourish next to Doncic and Irving. Last season for Brooklyn, O'Neale averaged 8.8 points, 5.1 rebounds, 3.7 assists, and 0.9 steals per game while shooting 38.9 percent from distance.
He would get consistent open looks playing next to Doncic and Irving every night, and he would strengthen Dallas' defense immensely.
Landing O'Neale at the trade deadline would be ideal for Dallas, as he is on an expiring contract, but he may come at a steep price. Contenders from all around the league will be calling Brooklyn about O'Neale at the deadline if they are shopping him, and he would make a big effect on any team trying to make a final playoff push.
Although O'Neale is a great player and brings elite defense and shooting to the floor, a teammate of his may be an even better fit on the Mavs, and that leads us to the next player that the Mavs could replace Tim Hardaway Jr. with by the trade deadline.