Minimum: 10 minutes per game
The true college experience, at least at Chapel Hill, now includes being rejected by John Henson. This spring, when a crew of Tar Heels played Twitter-publicized, outdoor pickup games against regular students, Henson was repeatedly asked to block their shots. "So I'd block one, and it would make their day," he says. The 6'10" forward used his 7'4" wingspan to swat, alter or challenge so many shots that as a sophomore he was named the ACC's defensive player of the year. The award was backed up in SI's study, in which Henson received the Heels' top defensive rating (84.9).
Henson excelled in four areas: Opponents shot just 30.6% against him (UNC allowed 40.5% as a team); he fouled at a very low rate for a big man whose primary role is to protect the basket, creating just 0.159 free throws per field goal attempt faced; he grabbed 10.9 defensive rebounds per 40 minutes; and was directly involved a higher percentage of possessions (24.0) than any Tar Heel. His efforts were key to North Carolina's ranking sixth nationally in defensive efficiency. Its most effective defender was also its most engaged.
A curious thing happened at the Tar Heels' annual award ceremony last April, though: The Carmichael-Cobb Award, which honors North Carolina's best defensive player, did not go to the ACC defensive player of the year. It went instead to center Tyler Zeller, whose traditional numbers (1.2 blocks, 4.4 defensive boards versus Henson's 3.2 and 6.9) did not illustrate the 7-footer's full value. To determine the winner, Carolina used its own ratings system that is no less intensive than SI's. Coach Roy Williams and his staff grade every possession using a system in which a player gets a minus for making a mistake, nothing for doing his job correctly or a plus for doing an exceptional job (a great rotation or a forced turnover, for example). Zeller graded highest in 11 of the team's 37 games. The next-best Heel had four. "Tyler does all of the little things that you can count on," Williams says. "His teammates trust him to be in position."
Henson proposes that he and Zeller—the team's second-ranked defender in SI's study—should be called Fire and Ice for their divergent defensive skill sets. "Fire, because I'm a shot blocker," says Henson, the only Tar Heel coaches allow to jump at shooters on the interior, "and Ice, because Z's a charge-taker." Zeller creates turnovers at a rate (19.7%) more than double Henson's, mostly in ways that don't appear in the box score: by stepping in front of drivers to draw offensive fouls and by deflecting or tipping post entries into the hands of teammates.
Because Zeller is supposed to be the first big man down the floor on UNC's fast break, his defensive rebounding rate is lower than expected, and while he doesn't hunt blocked shots, he walls up well enough that teams shoot only 37.6% against him. Combining Zeller's offensive skills (his personal efficiency rating is a team-high 120.1) with this new layer of defensive data makes Zeller one of the most valuable players in the nation, not just a complementary cog in the Carolina juggernaut.
National player of the year candidate Harrison Barnes ranked third in the defensive pecking order, but he was involved on a team-low 14.4% of possessions. Shooting guard Dexter Strickland was fourth among UNC's starters, although Williams—who reviewed the study—perceived that as a positive, because Strickland usually gets the toughest perimeter assignments. The player with easier backcourt matchups, point guard Kendall Marshall, had the worst DRating (91.0) of the five starters. "[Marshall] can't be a liability for us on defense," Williams says, and he made it an off-season priority for Marshall to get stronger so he could better contain penetration. But if UNC's point guard does get beaten off the dribble, Williams can take comfort in the knowledge that Fire and Ice will be waiting to issue blocks and charges, no requests necessary.
ADJUSTED DEFENSIVE RATING: 89.5