The numbers don’t lie: Spurs’ D has taken a dip

There’s no doubt the Spurs are coming off one of their worst defensive efforts of the season. They allowed Miami to hang 110 points on them in a convincing 110-80 loss that ranks as the team’s largest margin of victory of the season.

It continues a couple of noticeable trends. Miami hit 53.8 percent from the field, becoming the fourth consecutive team to improve the field-goal percentage from the previous game. A streak like that hasn’t happened for the Spurs’ defense all season.

The Spurs also have allowed their last four opponents all to score at least 100 points against them. That’s the second longest streak of the season, topped only by five straight 100-point performances allowed from Dec. 16-23.

But the best way to judge the effectiveness of a defense is to look at the number of points scored per 100 possessions.

Matt Moore of CBS Sports.com’s Eye on Basketball . And he found that the Spurs’ defense has taken a noticeable step back in its March games.

Moore  writes that the Spurs entered Monday night 7th in the league at defensive efficiency (which estimates points per 100 possessions, removing the element of pace and providing a more true image of defensive productivity). That’s not as good as Gregg Popovich’s defenses typically are, but it still ranks among the leaders in the league.

But they also entered Monday night’s game against Miami having averaged giving up 102 points per game in March, as opposed to their typical mark of 97. Their season defensive efficiency has been a solid 101.1.

In March games, the Spurs have averaged a 108.5 defensive efficiency, including marks of 117 to Memphis, 112 to the Lakers, 114 to Detroit and their worst score of 122 to the Heat Monday night.

Moore notes that the worst team in the league, the Cleveland Cavaliers, average a 110 defensive efficiency. So in a supremely small sample of the recent games, the Spurs are surrendering a defensive efficiency that would be the worst in the league if spread over the season.

And looking at the Spurs’ defensive efforts per game, there were some noticeably stolid efforts betrayed with huge breakdowns. Most notable was a two-possession series against the Heat capped by thunderous dunks by LeBron James and Dwyane Wade in the fourth quarter Monday night.

These defensive struggles are something that have rarely been seen around the Spurs franchise — especially in their championship seasons.

The Spurs will have their work cut out over the next several days to rectify those woes before facing Dallas, which ranks fourth in the NBA in field-goal percentage, seventh in 3-point percentage and 11th in scoring.

The Mavericks have had their own slumps in recent games, failing to score 100 in two of their last three games in losses to the Lakers and New York heading into their game Tuesday at Portland. But before that, the Mavericks had scored at least 100 points in 19 of their last 20 games.

The Spurs will get one more edge that should help their defense improve. San Antonio will be coming in on three days of rest for Friday’s game. And the Mavericks will be playing their third game in four nights Friday, after games against Portland on Tuesday night and Golden State on Wednesday.

The Spurs’ defense should improve. If not, Popovich might have some major worries heading into the playoffs.