In two of the past three games, the Minnesota Vikings defense has played poorly—to the point of letting down its architect, head coach Mike Zimmer. Since Sunday's game against the Dolphins, Zimmer has not minced words in just how he feels about the defense's performance.

"Defensively we were very, very poor," Zimmer told the Star Tribune after reviewing the game tape. "I'm trying to figure out how we can go from playing so good one week to playing so poorly the next week. That's kind of disappointing to me. But we're going to get back going and continue to find out more about these guys this as we get ready to go play Chicago."

Zimmer was pretty disgusted with the defensive performance in Miami. In fact, he was pretty frontal in his criticism of it, and he gave it some near all-time marks, but not the kind of marks you would aspire to achieve:

"That was the worst we've played all year, maybe one of the worst defensive performances I've seen in a long time, but definitely this year, for sure," he said.

Asked to diagnose the problems, Zimmer was at a loss and initially blamed himself, but then he recalled the penalties, which were certainly a problem.

"I don't know, maybe I had too much stuff in, maybe we were confused," he said. "But we had 11 penalties on defense alone. If you're going to have 11 penalties on one side of the ball, especially defensively, you're not going to win very many games. That was extremely disappointing. Until you stop beating yourselves, you're not going to beat anybody."

Zimmer appeared no less agitated at his Monday press conference than he did Sunday after the game. He takes pride in his defense and really seems to hold them to a higher standard than anyone else. When they do well, it is expected and there are things to work on. When they do poorly, he is frustrated, confused, disappointed and downright owly until it changes. Right now, he is struggling to figure out exactly what happened against the Dolphins.

"Sometimes it just bothers me when people don't do what you ask them to do," Zimmer said. "If we could understand as a group, as a team, as a unit, if we do what we're supposed to do, good things will happen. Throughout most of the season, the defense has done that. They've done what they're supposed to do, lined up and done this and done that, and for the most part good things have happened for them. So, those things bother me, mistakes bother me, penalties bother me, selfishness bothers me.

"I've tried to preach [that] the team is important and understanding your role and understanding where you're supposed to be. That's why we have this room in here is so that we can all understand what we're trying to get done--and that's what bothers me the most."

It's strange, and also a shame that the defense has struggled in the last quarter of the season. Up until this point, it had been the unit that basically kept the Vikings' season afloat while a rookie quarterback tried to figure out the NFL with an offense around him that was missing, injured or just underperforming.

For much of the season, the Vikings defense had ranked in the top 10 in the league in yardage allowed but is now 15th. The pass defense reached the fourth best—but it has now dropped to 8th, giving up 226.7 yards per game (allowing 377 passing yards against the Dolphins will do that). At one time, the defensive line was also near the top in sacks (now 7th with 40 on the season). It was formerly a defense that was ascending, but it is currently experiencing a steady decline.

So what happened? Interspersed between the terrible performance in Miami and a bad one against the Jets, the Vikings defense played well against the Lions (giving up just 233 total yards and 16 points). Did the defense which played well nearly all season simply overachieve during that time and is now regressing to the mean? Did the players lose their edge after being eliminated from the playoffs and then temporarily engage against the Lions to get Zimmer a divisional win? Are they now suffering from too many injuries (starters Anthony Barr, Sharrif Floyd, Brian Robison, Robert Blanton and Chad Greenway have all missed time recently)?

It could be all of the above. I am not sure what the answer is, and I certainly don't presume to know it when the head coach is somewhat confused himself.

"I think for the most part I know who they are," Zimmer said. "I don't know who they were Sunday. It's disappointing to me that, I mean we had guys who are normally good players that played poorly, I mean really poorly. That surprised me. Guys that you know you can count on that didn't play good, that's frustrating. I don't know. I don't know what it is."

Rest assured, Zimmer is going to find out what his defense is and who will be playing on it. There is one game left in the season, and that is all that remains for these players to put something on tape that Zimmer will perseverate over during the offseason.

We saw during the past offseason that Zimmer installed eight new starters on defense in an attempt to improve the bottom-feeding defense he inherited. With the pride Zimmer has put into the defensive side of the ball, he undoubtedly will make more changes this offseason.

Certainly Zimmer will look at the players' entire body of work on the season, but given his current mood, no one should take for granted that they are golden. But we can.

Harrison Smith, Everson Griffen and Xavier Rhodes have been playing at a Pro Bowl level for much of the season (even though they didn't get the votes needed to make it). Rookie Anthony Barr started all year until he was injured and became the lynchpin of the linebacking unit. Robison is a defensive leader and still valuable. Floyd and Gerald Hodges were both on the rise until their "undisciplined," "ridiculous" and "stupid" (in Zimmer's words) personal foul penalties in Miami. They had better be on their best behavior against the Bears.

Linval Joseph is safe, but he was being pushed by his backups most of the season. Jasper Brinkley did nothing to lose his job, but he didn't really flash either. Zimmer loves Chad Greenway for his effort and leadership, but his age and deteriorating skills could become a liability—at least as a starter. Andrew Sendejo, Robert Blanton and Captain Munnerlyn and even Josh Robinson need decent games against Chicago to wash a bad taste that may be lingering in Zimmer's mouth.

"At some point in time, I will get this defense fixed," he said. "It may not be this week, it may not be until middle of the year, but it will get fixed you can bet your butt on that."

Whether Zimmer wants to admit it or not, the future starts next Sunday for this defense. If the players want to be a Viking next season, they need to begin their audition against the Bears. Given the mood we have seen from the head coach this holiday week, expect his defense to respond with a decent performance.

Head over to Vikings Journal and check out the classic holiday-themed stories by AJ Mansour and Bo Mitchell and then join in the conversation on the Vikings Journal forums, where everything Purple is dissected and discussed.

Joe Oberle is a senior writer at VikingsJournal.com, covers the NFL for The Sports Post and is managing editor of Minnesota Golfer magazine. He is an author and longtime Minnesota-based writer.