Really it can be boiled down to something as simple as there was no need for two of this archetype, and JMike was the younger one and friends with Ace. Derek had his chance to take his leap and failed. He played pretty good D last year but there was always a ceiling how effective he could be on that end due to his skinniness. JMike has a stronger build and was already stellar defensively as a freshman, something Derek was not. Also, even though not really backed up by stats yet but I just feel more comfortable out there with JMike, at least he showcases touch on layups and in the intrasquad scrimmage showcased a floater that I hope to see more of. Then the last thing is it seems people really gravitate towards JMike, where people seemed to not have much respect for Derek last year. Ultimately, JMike had the right connections and more willing to play the current role asked than Derek would have and he at least has a bit of upside to improve