EARTH CITY, Mo. — The St. Louis Rams defense has become the talk of the NFL for good reason. So much so that the Rams enter Thursday night’s home game against the Arizona Cardinals as 3 1/2-point favorites. That’s unusual for a team with six wins to be favored over a team with 10.

But the Rams played the Cardinals tough in Week 10 when a 14-10 lead in the fourth quarter quickly turned into a 31-10 loss thanks to one big Arizona offensive play for a touchdown and two defensive touchdowns against the Rams’ offense.

Both teams rank in the top five in the NFL in offensive points scored against the defense, so this matchup shapes up as one that should be another defensive battle.

When head coach Jeff Fisher was asked Monday if this is the level of defense he expected to see this season, he said simply, “I want to see (it) again. I think we need to keep playing and keep preparing the way we are. When you’re getting the turnovers and you’re getting the third-down stops and you’re stopping the run, that gives you a chance.”

In the first seven games of the season, the defense allowed 168 points (24.0 per game). In the last six games, the total has been 54 (9.0 points per game). The reasons for the improvement are varied.

–The emergence of rookie defensive tackle Aaron Donald.

The first-round pick didn’t start until the fifth game of the season, but since then has been a consistently disruptive force. A candidate for defensive rookie of the year, Donald has 58 tackles with 16 for loss, and his 7.0 sacks are the best among NFL rookies. He also has 21 quarterback pressures and 10 quarterback hits.

Asked if he has ever had a rookie as advanced as Donald, Fisher said, “Well, not inside on the defensive line, no. The way he’s playing is pretty impressive, week after week after week. That’s what we thought we would get out of him and I think we’ve got more than we thought. He just loves to play and he plays hard. He doesn’t draw attention to himself. He’s really smart and very talented physically. Those two traits result in the plays that he’s making.”

On whether Donald could be defensive rookie of the year, Fisher said, “I said that in the spring when I saw him on the practice field. I went on the record to say he has a chance to be defensive rookie of the year. I haven’t changed since.”

–The return of defensive end Chris Long.

Long suffered an ankle injury in the season opener that required surgery, and he wasn’t able to return until Week 13. He’s only played about half the snaps in his first two games back, but he has made an impact and helps keep other linemen fresh.

–The improvement in the secondary with cornerback Trumaine Johnson healthy, the steady progress of rookie cornerback E.J. Gaines and the acquisition of safety Mark Barron.

Said Fisher, “The depth is obviously there now at both spots. At the corner spot, as well as at the safety spot with Mark. They’re all contributing. They’re playing well together. E.J. is playing inside very, very well. They’re communicating. Both the corners are showing up in run support and making plays on balls and playing team defense and scheme defense and recognizing things. We’re in good shape there.”

That depth resulted in Lamarcus Joyner and Marcus Roberson being healthy inactives against the Redskins Sunday.

–Linebacker Alec Ogletree stepping up after a slow start that Fisher attributed partially to him being out of shape when he reported to training camp.

As for his improvement, defensive coordinator Gregg Williams said, “He’s done a very good job. When you say mistakes, it’s that he’s just continued to improve his technique also. Nobody makes a mistake on purpose, certainly not him, but he’s refined some of his techniques very well. He’s got great burst, great explosion and I think his comfort (level) about what we’re doing and why we’re doing it has fit in very well here, especially the last five or six weeks. He’s very comfortable in knowing what to do, when to do it, when to pull the trigger, when to be maybe a little bit of a risk-taker. He’s done a very good job of that.”

Now, as Fisher said, he just wants it to continue.