Posting an ESPN insider article for those w/o insider

Putting the 'D' in Wildcats

WHEN T.J. McCONNELL finished his sophomore year at Duquesne without a 2012 postseason appearance, the gritty 6-foot-1 guard decided he wanted to play at a higher-level program with NCAA tournament potential. But when he announced that his preferred schools were Arizona and Virginia, those who remembered him as an incoming freshman -- a guard so skinny he constantly had to rearrange his jersey to prevent it from slipping off his shoulders -- thought he was crazy. Sure, McConnell had since put on 20 pounds and was a starter for the Dukes, but many believed he didn't have the chops to compete in the Pac-12 or ACC.
How wrong they were. The Pittsburgh native's reputation as a ball-hawking, all-Atlantic 10 defender sold Arizona coach Sean Miller. And since taking the floor this fall, the redshirt junior has revitalized a team that may have boasted a strong offense, led by guard Nick Johnson, but sorely lacked the defensive toughness to compete for a national title.
Consider Arizona's loss to Ohio State in the Sweet 16 last season: In the final seconds, a poor pick-and-roll D led to a longer-than-necessary double of Aaron Craft, resulting in a wide-open, game-winning 3 from LaQuinton Ross. Those kinds of defensive miscues are what made Miller turn to McConnell for help. "One of the things we have had a problem with in recent years that I believe T.J. can solve," Miller told the AP in the preseason, "is his ability to defend -- not only the man he is guarding, but just playing team defense."
So far, McConnell's addition has been transformative: the Wildcats, 25-2 through Feb. 23, had the nation's lowest defensive efficiency rate and were holding opponents to a tepid 42.1 percent effective field goal percentage. As opposed to the backcourt of Mark Lyons and Nick Johnson a year ago, McConnell is less a scorer (8.1 ppg) and more a facilitator (5.6 apg) whose contributions begin as soon as a Wildcat hoists a shot. McConnell is often positioned to prevent a transition bucket, making opponents pull back and run their half-court sets. Says one Pac-12 assistant, "They do a great job of making you play 5-on-5 as much as possible."
McConnell is also a nightmare for teams looking to score from downtown. He excels at closing hard on a shooter or plugging a gap to keep the ball beyond the arc. Both times Arizona faced Colorado, McConnell's play was crucial in limiting Askia Booker and Jaron Hopkins to just 10-of-37 field goals. "McConnell gets spacing and how to pressure the ball," says one opposing coach.
His aggressive play on pick-and-rolls, though, is a key reason Arizona should be able to weather the loss of forward Brandon Ashley, who is sidelined with a broken foot the remainder of the season. That was evident during the second half against Cal on Feb. 1, when McConnell forced a turnover after he shot the gap during an attempted handoff to Justin Cobbs. McConnell, says another assistant, "doesn't bail out on screens" and has accountability for his own man.
Since Miller has experimented with both Rondae Hollis-Jefferson and Gabe York replacing Ashley in the lineup, defensive breakdowns aren't the main reason for the Wildcats' losses to Cal and Arizona State (after spending eight weeks at No. 1). Rather, the offense has slipped considerably; Ashley led Arizona in 2-point jumpers before his injury.
The team's effective field goal percentage has dropped by more than two percentage points, and without Ashley's perimeter shooting to create spacing, the offense is stagnant. Johnson, in particular, is struggling with a packed-in half court, converting just 37 percent of his 2's. Arizona's offense hasn't been overwhelming this season, but without that balance, there has been more pressure on the team's D.
Still, most coaches who've scouted the Wildcats believe the team is the nation's toughest. "McConnell has made them a physically tougher team," says one coach, "and without getting them to rotate their defense, they are a bear." Which is saying a lot for the skinny transfer from the Dukes.