NFL chief medical officer Dr. Allen Sills said Tuesday that 94.1 percent of players have been vaccinated against COVID-19, via Tom Pelissero of NFL Network.

Sills said the goal is still to reach 100 percent.

"I think we're seeing a substantial effect, in a beneficial way, of the vaccines," Sills said Tuesday.

The NFL did not mandate vaccines for players, but the league created stricter protocols for those who were unvaccinated, including more frequent testing and travel restrictions.

The NFL has hoped to limit the spread of COVID-19 this season after numerous games were rescheduled in 2020 due to outbreaks. The seeming lack of spread among players and staff during games has been a major plus in accomplishing this goal.

"We still don't see any evidence of outdoor on-field transmission," Sills said.

The league has still dealt with some cases of COVID-19, including this week with the Green Bay Packers. Defensive coordinator Joe Barry tested positive and receivers Davante Adams and Allen Lazard were both placed on the reserve/COVID-19 list this week.

Arizona Cardinals head coach Kliff Kingsbury also recently tested positive for COVID-19 and missed his team's Week 6 game against the Cleveland Browns.