Stan Van Gundy, Pistons’ players frustrated by team’s poor defense. As they should be.

In the month of November, the Detroit Pistons allowed just 103 points per 100 possessions to their opponents.

In their last 15 games, they have allowed 113.4 per 100. Only the Nuggets have been worse.

The Pistons have gone 4-11 in that stretch, falling out of the playoffs (they are three games back of the eight seed as of this writing). Stan Van Gundy is a defense-first coach, and he is frustrated, as reported by Aaron McCann of Mlive.com reports.

“We can’t stop anybody. We just can’t,” Van Gundy said. “The first 21 games, we were the second-best defensive team in the league. And now we’re one of the worst. I’m frustrated -- not with our players, I’m frustrated with myself. That I can’t figure this out. I mean, we literally can’t stop anyone. Ever.”

Point guard is Reggie Jackson (who has played better of late after missing the start of the season) echoed those comments.

“It has to be fixed -- or it’s going to be a long (expletive) season,” Jackson said. “It’s been a season from hell so far. So it’s going to be a long-(expletive) season if we don’t find a way to fix it.”

So what’s the problem?

“A little bit of everything,” Jackson said. “Sometimes we have mental breakdowns. Not sticking to our principles. I think sometimes we’re not just playing simple basketball and understanding who we’re guarding or where we want to be. And I think just, too many times we’re letting our offense and a lack of making shots at times really dictate how much effort we put out on defense. We can’t do that.”

Teams have been killing the Pistons from three of late — shooting 47 percent in the last nine games —something that is a bit of a statistical fluke and will regress over time. But the problems go far beyond that.

We came into this season thinking the Pistons had a formula with Andre Drummond in the middle and four guys out, but this season that equation hasn’t added up. For example, when Drummond and Tobias Harris are on the court together, the Pistons get outscored by 7.6 points per 100 possessions. Van Gundy the coach should be frustrated, but the real work in getting this team working again may fall to Van Gundy the GM.