Could this be the end of the One-and-Done rule? What does this mean for the Portland Trail Blazers? With the current Collective Bargaining Agreement running through 2023-24, and a looming mutual opt-out date this December, the NBA and NBPA have made strides on two key subjects, according to Shams Charania of The Athletic. Sources: NBA and NBPA in serious talks on new items for potential Collective Bargaining Agreement: – Draft age eligibility from 19 to 18, return of high school-to-NBA – Measure that allows players citing mental health similar to physical injury More: https://t.co/ecABKkat2H — Shams Charania (@ShamsCharania) September 19,…