I definitely think this scenario is more likely than Poole supplanting MAAR. If poole shoots within a few percentages of Duncan, and if Poole is better at guarding 3s than Duncan is at guarding 4s (assuming Matthews brings equal utility guarding the 3 or 4), then I can see Poole eating into Duncan’s minutes.
Though it might be even more likely that +Livers/-Duncan brings more utility than
+Poole/-Duncan. Either way, really hope one of the 3 freshman hit and let Duncan go back to his bench sniper role, by midseason