Nobody is going to stop LeBron James; he remains the single best player walking the face of the earth. After his mid-season hiatus, he has played like it.
But the Chicago Bulls have the second best one-on-one defender to throw at LeBron James in Jimmy Butler. (Kawhi Leonard gets the top spot.) Out on the perimeter, Butler can make life difficult for LeBron (again, as much as anyone can, LeBron shot 64 percent on contested shots in the first round).
The problem is LeBron is so strong he can post Butler up, and with a lot of LeBron at the four that could be trouble for the Bulls. The Cavs flexibility is key for them in this series.