General Manager Rick Spielman said Wednesday the 0-3 Vikings are close to getting the season "turned around," especially on defense where head coach Mike Zimmer's group is allowing 34 points and 440 yards per loss so far.

Spielman said his optimism is rooted in Zimmer and the coaching staff's ability to tailor defensive schemes to the player's skill sets, a process dragging longer into the season as Zimmer "learns what the players can do" after a summer with limited practices and no preseason games. The Vikings haven't finished a year worse than 11th in points allowed since Zimmer was hired in 2014, and they rank 31st entering Week 4.

"We're improving each week," Spielman said. "We have a lot of new faces, a lot of new starters on the defense. Coach Zim and the players down in the locker room have a very strong belief that we're going to get this turned around."

Previously, veteran defenses have given Zimmer the luxury of sitting young players until they're ready. But this year's roster turnover combined with injuries to defensive end Danielle Hunter and linebacker Anthony Barr have expedited learning curves, according to Zimmer, while extending the process of finding what coverages, blitzes and game-plan approaches work best.

"It's taken a little longer," Zimmer said. "You anticipate that you can get everybody in line and understand everything that you're trying to do with them pretty quickly, but with some of the young guys that we have this year, it's taken a little bit of time."

Protocol violators face suspension

Troy Vincent, the NFL's executive vice president of football operations, sent a memo to all NFL teams Wednesday reminding them of gameday protocols that include wearing face coverings at all times, adding individuals who break the rules could be suspended and teams could lose future draft picks.

"It's a message on how important this is and how important it is to make sure we're doing everything that we can control," Spielman said. "There's been a lot of hard work done from the science that tells you this is the safest way we can get through a season, and it's everybody's responsibility to follow those protocols. So, when people aren't following those protocols, that's what can get frustrating."

Last week, four head coaches — the 49ers' Kyle Shanahan, Broncos' Vic Fangio, Raiders' Jon Gruden and Saints' Sean Payton — were fined $100,000 apiece, and their teams fined $250,000, for violating the mask policies.

Dantzler returns sort of

The Vikings didn't practice Wednesday, but submitted an injury report to the league estimating the participation of their injured players. The good news for the Vikings is rookie cornerback Cameron Dantzler would've returned, the team's estimated, if the Vikings practiced from a rib injury that had kept him sidelined since the Sept. 13 loss to the Packers.

Dantzler was listed as limited, while cornerbacks Mike Hughes (neck) and Kris Boyd (hamstring) were estimated as non-participants. Hughes' neck injury has kept him out since the Sept. 20 loss to the Colts, while Boyd dealt with a hamstring injury last week while playing 38 defensive snaps [51%] against the Titans.

The Texans practiced Wednesday without defensive end Charles Omenihu (knee).

'It's unprecedented'

Texans coach Bill O'Brien got a call from the league office this week updating him on the Vikings' situation and telling him to prepare his team for Sunday's game in Houston.

When asked about hosting the Vikings, O'Brien noted ongoing uncertainty that just affected the Texans during last weekend's trip to Pittsburgh.

"It's unprecedented," O'Brien said. "We dealt with some things in Pittsburgh, where we had some positive tests and we had to get guys up at four in the morning to do point-of-care testing. Those two tests that we had positive ended up being false positives.

"Maybe I shouldn't be talking about it, but I think it's important to talk about it because this is what we're all dealing with as organizations."