LOS ANGELES - Until the New Year rolled around, Sean Miller's defense was pretty much right on schedule.
The Wildcats went undefeated in nonconference play with the stiffest defense Miller had seen yet in his four seasons with the Wildcats: Arizona allowed opponents to score just 59.2 points per game and shoot only 38.9 percent from the field before Pac-12 play began.
While Arizona's three-point percentage defense slipped to 35.1 in nonconference play this season from 28.5 percent overall last season, that was in part because of some early troubles behind the arc that the Wildcats appeared to have fixed.
For the most part, as evidenced best by Nick Johnson's game-saving swat against San Diego State, the Wildcats' D was there when it had to be.
That was also the case over Miller's five seasons at Xavier, where the Muskeeters generally improved each of his five seasons to the point where they posted the country's eighth-best defensive field goal percentage (38.8) in Miller's final season of 2008-09.
"At Arizona, our first team wasn't any good defensively in any way shape or form, but the second year we got better," Miller said. "Even last year, as much as everyone can point to us pulling up short, if you look at our defense, we really improved. And this year we've really improved."
Now Miller has a team that has allowed opponents to shoot 50 percent or better in five of its last 11 halves of basketball, including both halves Wednesday when USC beat Arizona 89-78 by shooting 61.1 percent overall.
Suddenly, the progression has turned to regression.
"We have some guys right now who are in the tank," Miller said. "It is really hard right now, whether it's conceptually, effort, being in the right place, being able to get stops. … It is a real chore for our team right now."
Here are five theories of what's going wrong:
1. There are technical lapses. Miller and all three of the UA players made available for comment Wednesday - Solomon Hill, Kevin Parrom and Grant Jerrett - indicated that the bottom line is that effort and toughness is lacking.
But there are a few specific, simple things that suddenly just aren't working right.
"We just have to run fast, play hard," Miller said. "When a guy shot-fakes, don't jump. When a guy runs full speed off one leg, you gotta draw a charge. You gotta secure rebounds with two hands. Block out."
Miller indicated that his last two rotation players, forward Angelo Chol and guard Gabe York, didn't help themselves in those areas, either.
"We want them," Miller said. "I think Gabe went for a shot-fake and in that role that we're counting on you, there's dependability. Angelo's gotta make layups, catch it with two hands.
"But it's not just them. It was a team loss in every way, shape or form."
2. They aren't tough enough. This one particularly eats away at Miller, who famously once reminded the Wildcats that "nastiness is required" after they beat Texas to reach the 2011 Sweet 16.
"Toughness isn't punching someone," Miller said. "Toughness is being able to perform under game pressure when the chips are really down in late February, early March. (If you can) compete and play hard, that's when you're a tough player, a tough kid."
3. Fatigue may be setting in. Arguably the Wildcats' MVP through the first half of the season for what he did on both sides of the ball, Johnson scored in double figures just once during February. Meanwhile, opponents scored more often against a defense he was leading.
When asked his opinion of Johnson's recent play, Miller said "not good" and pledged to get him to play better. If part of Johnson's issue is physical - he has been heavily relied upon and was ill for the Feb. 2 game at Washington State - Miller has a possible cure for that, too.
"One thing we can do to help his fatigue is not play him as much," said Miller, who played Johnson for just 23 minutes on Wednesday.
4. They're zoned out. Not in a literal sense, though it is worth noting that UA tried to shake things up by throwing out an uncharacteristic zone defense briefly on Wednesday, which Miller said "wasn't the answer."
Instead, the Wildcats may just not be absorbing some things mentally.
Miller noted that UA has now played 28 games, has practiced since October and had the benefit of 14 workdays before and during their summertime Bahamas trip yet "we couldn't rotate on a side ball screen."
As much as he reminds them how to do it, that isn't working, either.
"Some of it is we've won so many games that (players think criticism is) like, 'That's just Coach being Coach.'" Miller said. "That's no longer the case."
5. The seniors can only do so much. It was no coincidence that the three players logging the most minutes Wednesday were UA's three seniors.
Hill, who poured out another box score-filling effort on Wednesday with 21 points, six assists and five steals, said the team's effort was "more than frustrating" because he likely won't have a chance to cut down the nets at McKale Center next week.
"With so many young guys, they don't really understand the effort and how much sacrifice that goes into winning something like" a Pac-12 title, Hill said. "It has to be every play. You can't take a couple of plays off, because that's when a guy can get going."
"It's tough, man, when it gets to March, those guys they know they're not coming down this road again," Miller said. "That's right now why it's such a bad situation with us just because the things that we've done so well have left us, especially on defense.
"We've lost what we once had."
On StarNet: See more photos from Arizona's loss to Southern California on Wednesday at azstarnet.com/gallery
• Who: No. 11 Arizona at UCLA
• When: 7 p.m. Saturday
• TV: ESPN
• Radio: 1290-AM, 107.5-FM
Arizona's defensive dropoff
2013 stats Opp FG% Opp 3FG Opp TO Opp PPG
Nonconference 38.9 35.1 15.6 59.2
Conference 43.0 37.3 13.1 66.3
Overall 41.2 36.2 14.2 63.2
Sean Miller's defensive resume:
Year Team Opp FG% Opp PTS
2012-13 Arizona 41.2 63.2
2011-12 Arizona 40.6 62.7
2010-11 Arizona 44.4 67.9
2009-10 Arizona 43.7 72.0
2008-09 Xavier 38.6 61.9
2007-08 Xavier 41.0 63.4
2006-07 Xavier 43.1 65.5
2005-06 Xavier 39.6 63.4
2004-05 Xavier 43.3 65.0