Vikings receivers are getting healthier.

One reinforcement, K.J. Osborn, appears likely to return for Sunday night's game at Denver, but head coach Kevin O'Connell said Wednesday it's too soon to determine whether receiver Justin Jefferson will be available against the Broncos.

Osborn, who missed Sunday's win against the Saints due to a concussion suffered Nov. 5 against the Falcons, was a full participant in practice Wednesday. O'Connell left open the possibility of Jefferson, who was listed as limited, playing based on increased practice reps.

"We'll see how he responds to that," O'Connell said. "A little bit more [Thursday] and then throughout the week. We're kind of in that day-to-day, kind of ramping him up phase now. We'll determine if it's possible at all to have him for this weekend."

Second-year receiver Jalen Nailor returned last week from a seven-game absence due to a hamstring injury. Nailor started in Osborn's spot and caught his only target for 16 yards, but offensive coordinator Wes Phillips said he was getting open more often.

"It's been a while since I got to suit up," Nailor said. "It felt good to get back into the rhythm and flow of the game."

Running back Alexander Mattison did not practice Wednesday because of a concussion suffered against the Saints. O'Connell said he wants to establish the run in Denver, where the Broncos defense has allowed a league-high 1,226 rushing yards to running backs this season, according Pro Football Reference.

Running backs Ty Chandler and Kene Nwangwu, among the fastest players on the team, could shoulder more carries.

"Kene has maybe even a different element," Phillips said. "Ty's really fast, but Kene when he hit the edge there you could kind of feel all their guys say, 'Oh, man.' He was outrunning their angles."

Calf issue sidelines Evans

Cornerback Akayleb Evans did not practice due to a calf strain that limited him against the Saints. Rookie Mekhi Blackmon, whose first NFL interception helped seal the win, could replace Evans again if needed against the Broncos. Blackmon said the confidence of the defense has grown with success. The Vikings rank 13th in yards allowed and 14th in points allowed.

"First three weeks it felt like we weren't really comfortable [in the system]," said Blackmon, a third-round draft pick. "But up to this point, we've been trusting it. [Defensive coordinator Brian Flores] has been telling us it's going to hit, just keep trusting it, and up to this point we've been doing really good."

Tight end T.J. Hockenson (ribs) and linebacker Brian Asamoah II (ankle) were limited. Defensive lineman Dean Lowry (groin) is on track to return from a two-game absence after fully practicing. Kicker Greg Joseph had an excused absence due to a personal matter.

Mullens practices

All three quarterbacks — Joshua Dobbs, Nick Mullens and Jaren Hall — were on the Vikings' initial injury report on Wednesday, but O'Connell said all three could be available in Denver. Dobbs will start despite an ankle injury; he was a full participant. Hall was limited in his first practice since suffering a concussion in the Nov. 5 win in Atlanta.

The Vikings opened the three-week practice window for Mullens, who has been on injured reserve since Oct. 11 due to a lower back strain. He can be activated anytime within the next three weeks.

"Hopefully we can have all three of those guys," O'Connell said.

Cousins' involvement

Quarterback Kirk Cousins is just two weeks removed from Achilles surgery, but he has already attended some meetings at TCO Performance Center in Eagan, according to O'Connell, who said he wants the 35-year-old Pro Bowler involved at the team facility.

"I'm giving him projects," O'Connell said. "Having him be a part of it. He knows our offense — he knows it as well as any of us pretty much. ... It is kind of similar to our normal dialogue of Monday and Tuesday and as he gets into his tape study, I just asked him, 'I just want you to be involved. I just want you to be around our team. Be around.' He is going to start traveling when he gets cleared to do that. I think it will be a huge bonus for everybody to have him around."