On the defensive side of the court is the area where it may be hardest to project Carter-Williams and, outside of the overall depth in the Syracuse backcourt likely the single biggest reason for his limited minutes as the season progressed.
Despite his average wingspan, Carter-Williams has the size and foot speed to be a disruptive force on the perimeter, and he did do a good job of forcing turnovers during his freshman season. His overall dedication on this end can be in question, as he at times appears to lose focus. He's also not particularly good at working through screens, something he'll have to work to improve going forward, especially with his size.
His weight, listed at 176 pounds according on Syracuse website, is a big detriment for him on the defensive side of the ball as well, particularly if he's asked to defend shooting guards at the next level. Whether or not he has the frame to add substantially more weight to his skinny frame is one of the things to watch going forward.