MINNEAPOLIS -- Half a season into Mike Zimmer's first year as the Minnesota Vikings' head coach, the team's defense in the midst of an impressive turnaround.

A group that allowed the most points in the NFL last season has improved to 17th overall, having allowed 173 through eight games. The Vikings fare even better in yards allowed, where they've gone from 31st to ninth, and third-down conversions, where they've improved from 30th to seventh. So far this season, the Vikings have given up a first down on just 36.5 percent of third downs, after failing to get off the field 44.2 percent of the time last year.

After sacking Tampa Bay Buccaneers quarterback Mike Glennon five times on Sunday, the Vikings now have 25 sacks, which ties them with the Jacksonville Jaguars for the second-most in the league (last season, they tied for 13th overall with 41 sacks). Linebacker Anthony Barr leads all rookies with three sacks, defensive tackles Tom Johnson (five sacks) and Sharrif Floyd (three) have already hit career highs, and defensive end Everson Griffen is third in the league with eight sacks. Safety Harrison Smith is tied for third in the league with three interceptions.

Zimmer has shown little interest in comparing his defense to what the Vikings did last year and has maintained he came to Minnesota with no expectations of how good the group could be. He said he typically doesn't even look at statistics for another month, when there's a larger body of work.

"Talk to me at the end of the season and I’ll tell you what I think," Zimmer said. "There’s a long way to go. I never look at defensive rankings or anything like that until at least Thanksgiving. I think by then you kind of know what you are. I hope we can get better than what we are now."

But after what the Vikings had last year -- an often toothless unit that blew five last-minute leads and couldn't stop drives when it had to -- it's striking to look at how much the group has improved this year. With so many key players (Griffen, Floyd, Linval Joseph, Barr, Xavier Rhodes, Smith) all 26 or under, there's plenty of reason for optimism about the team's defensive foundation.