RICHMOND — On the first day of training camp, Washington Football Team Coach Ron Rivera walked to the podium for his introductory news conference wearing a black mask. As of Monday, his team ranked last in the NFL in player vaccination rate at 60 percent, according to a person with knowledge of the situation.

The 59-year-old coach, who battled a form of skin cancer last season, sounded exasperated.

“I’m truly frustrated,” Rivera said. “I’m beyond frustrated. One of the reasons I walked in with a mask on is I’m immune-deficient. … When I’m in a group and the group’s not vaccinated or there’s a mixture, I put the mask on, and I do that for health reasons because nobody really knows [about the new delta variant]. I have to do that. And I just wish and I hope that our guys can understand that.”

The setting of these comments — an in-person news conference in Richmond — represents the dual realities the NFL will try to navigate this season. There is a desire for normalcy, for fewer Zoom meetings and the return of fans; but there’s also the reality of the resurgence of coronavirus cases nationally. The NFL said Tuesday that 85 percent of all players have received at least one dose of the coronavirus vaccine.

Washington also placed right tackle Cornelius Lucas on the covid-19/reserve list Tuesday. It’s unclear when he’ll be eligible to return or whether he was vaccinated. Lucas took almost all the first-team reps at right tackle during organized team activities and started several games at left tackle last season.

Despite lagging behind the rest of the league, Washington’s player vaccination rate represents a significant jump from early July, when it was 36 percent, according to a person with knowledge of the situation. Rivera, who said Washington’s coaches and staffers were nearly 100 percent vaccinated, said he couldn’t explain why his players’ rate was so low. The team does not plan to identify players’ vaccination status, he added, but Rivera does intend to have individual conversations.

“I’m not going to tell anybody what to do,” Rivera said. “I’m going to try to understand them and give them some reasons why I think it’ll be a good thing. And we’ll see how it goes. I hope we can get to these guys and get them to understand, really, it’s not just for them, but it’s for the people around them. And that’s the thing, hopefully, that will get their attention.”

The low vaccination rate could become a competitive disadvantage. Rivera pointed out he could wake up on a Saturday morning and find out five starters can’t play that Sunday, like what happened to the Denver Broncos in late November when Kendall Hinton, a wide receiver from the practice squad, was used to play quarterback after the entire QB room was quarantined.

Tension over the vaccine has the potential to flare among players in locker rooms. While the NFL has not mandated players receive the vaccine, as some government officials and health groups have begun to do, it sent a memo last week saying if a game was canceled this season because of a coronavirus outbreak among the unvaccinated and could not be rescheduled, the team with the outbreak would forfeit.

“You’re risking not just your paycheck but other people’s paychecks, too, if there’s no game played,” Rivera said. “That’s something that we all have to think about.”

In early June, Rivera brought in Kizzmekia S. Corbett, an immunologist and leading coronavirus vaccine researcher, to give a presentation to players about the vaccine. Rivera said he wanted to educate his players because some of them, from a different generation, get news from social media. But the presentation didn’t sway some players.

Notably, defensive end Montez Sweat said he did not appreciate the team trying to sway him and he remained skeptical about the vaccine. Other NFL players have expressed their wariness about getting the vaccine. After the league’s forfeit memo, Arizona Cardinals wide receiver DeAndre Hopkins and Buffalo Bills wide receiver Cole Beasley took issue with the league’s decision on Twitter.

For Rivera, one of the most frustrating parts of the situation is the contrast to the team’s success navigating the pandemic last season. The team avoided outbreaks for most of the season, and both the positive tests it had came from players not on the 53-man roster.

“We’re not where we want to be,” Rivera said. “A lot of guys have a lot of questions, unfortunately. They haven’t gotten the answers that they should have by now. We need to do a job of trying to make sure we can inform them and help them make an educated decision.”