Defense is a full-team concept. You’re only as strong as your weakest link, especially in a switch-heavy system like what NU runs. It’s not a scheme where you just park your best defender on their best scorer and call it a night. Everything is built on switching, early help, and instant reads. That demands constant communication and a shared understanding of where the next rotation is coming from. With eight guys in their first year in the system, that stuff is naturally going to take time.
Mullins and Gelo are clearly two of the better perimeter defenders on the roster, but you need more than just two guys to build a real defense. Mullins’ offensive game still leans heavily on his athleticism in transition. The jumper has not become a consistent weapon yet, and in the half court he tends to play at one speed, fast. He needs more change of pace on drives and even on his off-ball movement to keep defenders off balance. Gelo, on the other hand, gives you the next-best defense on the team and is less limited offensively. He’s earning the minutes over Mullins right now.
That, plus some instant offense from Green or KJ, could flip momentum and spark inspired team defense. The 4 is locked up by Martinelli and Singleton, and that pairing also soaks up a lot of the minutes at the 3. That leaves four guys battling for the remaining rotation minutes at the 3 and essentially all of the minutes at the 2.