The Vikings defensive backs seem to have established a pretty good chemistry over the past couple of weeks. Or at least it appeared, before a talk with coach Mike Zimmer.

“We had a fight yesterday, so I don’t know,” Zimmer said Thursday.

That practice flare-up aside, the group seems to be on the same page as it faces Sunday’s tall task in Denver against quarterback Peyton Manning, a five-time MVP. The Broncos are 3-0 and have 755 passing yards and five touchdown receptions in those victories.

Vikings defensive backs appear unconcerned. Safety Harrison Smith smirked when asked about the fight and said, “Yeah, there’s nothing that kind of lingers. That stuff might happen, but we get over it.”

“Everybody’s right there on the same page. Everybody is together. We really do have a good chemistry and a good feeling in the room. No [grudges]. On to the next play, pretty much.”

And the next man. Rookie cornerback Trae Waynes and safety Robert Blanton both stepped in for injured teammates in the second half against the San Diego Chargers and the defense didn’t miss much of a beat in a 31-14 victory. They’ll likely be asked to fill holes again Sunday.

Safety Andrew Sendejo is out because of an injured knee, and reserve cornerback Jabari Price (shoulder) is also sidelined. That could mean playing time for young safety Antone Exum behind Smith and Blanton.

The DBs have combined for 86 tackles and seven pass deflections in the Vikings’ 2-1 start.

“The chemistry is coming along great,” cornerback Xavier Rhodes said. “We just click. We talk among each other. We don’t hold anything against each other. We all know a play is going to be made here and there, but we need to build each other and lift each other’s spirits up.”

Back-to-back strong efforts from the Vikings run defense forced Detroit quarterback Matthew Stafford and San Diego’s Philip Rivers to rely heavily on the passing game the past two weeks, and the Vikings secondary limited big plays.

“That’s the goal and we’ll continue to have that goal,” said Sendejo, who earned the starting safety job before his injury. “Keep everything in front of us. That’s your main job as a defensive back. All throughout the week we’re communicating and just carrying it over into the game. I think we do have good chemistry back there.”

Zimmer has been critical of Exum, who in the preseason seemed likely to play a larger role this season. When asked Friday, Zimmer said, “He’s a good athlete, he’s a physical tackler, pretty good cover skills … it’s still an ongoing process, I think. The communication, the recognition, it’s really that, it’s not physical things.”

Opponents have totaled 760 passing yards with four touchdowns and been picked off twice by the Vikings. Manning and his top receivers — Demaryius Thomas (24 receptions for 268 yards) and Emmanuel Sanders (22-239) have caused problems for opponents.

Rhodes knows the secondary faces a big challenge, especially with Sendejo out and Rhodes just days removed from a concussion suffered in Sunday’s victory over the Chargers.

“They have some of the top receivers in the league,” Rhodes said. “Manning knows everything about his guys, so we have to be good as a unit and come together and realize what we’re going up against.”