9. Can't afford to trade: Dereck Lively II
The Dallas Mavericks' best move of the offseason came when they selected Dereck Lively II with the No. 12 overall pick. Dallas originally had the No. 10 pick but traded back in the draft while shedding Davis Bertans' contract and gaining a traded player exception.
Dallas landed their rim protector of the future with this selection, but Lively II has also been a phenomenal fit next to Luka Doncic as the two dominate in the pick and roll.
At first, Lively II was just a lob threat at the rim, but now he has developed some aggressiveness in the short roll that has allowed him to be more of a scorer when he isn't catching lobs. Against Oklahoma City, Lively II had multiple plays in which he caught the ball and the short roll and finished at the rim through contact with a dunk or a layup.
He has been one of the most important players on the Mavs this season, and his ability to do exactly what Dallas asks of him combined with his undeniable chemistry with Doncic and Kyrie Irving makes him someone the Mavs can't afford to move.
He has future all-star written all over him, and the Mavs couldn't have drafted a better player than they did with the No. 12 overall selection. If his offensive game continues to develop, watch out.