ENGLEWOOD, Colo. — As the Broncos moved Sunday's practice indoors because of air-quality issues in Denver, wide receiver Tim Patrick joined the team's growing list of injured players, as he watched the entire session from the sideline.

"He's got a groin issue, I believe," Head Coach Vic Fangio said after practice. "Nothing serious, but just taking the precautions."

Fellow receivers Diontae Spencer and Tyrie Cleveland also observed practice from the sideline, as they recover from knee and backside injuries, respectively.

The team was without several defensive linemen — Mike Purcell (ankle), Marquiss Spencer (ankle), Deyon Sizer (hamstring) and McTelvin Agim (groin). After participating in the team's stretch period, Purcell did run himself through some defensive line drills on air while wearing his helmet as he nears his return.

Agim, Fangio said, could be out longer, to the extent that he may not be able to practice when the team travels to Minneapolis for joint practices with the Vikings.

"He's probably going to miss a few days," Fangio said. "I don't know if he'll be able to work in Minnesota."

Other players who did not practice Sunday included cornerbacks Kary Vincent Jr. (hip) and Mac McCain III (hamstring) and linebacker Josey Jewell (groin). Outside linebacker Von Miller and kicker Brandon McManus were also absent from practiced, as they were excused to attend Sunday's Pro Football Hall of Fame enshrinement ceremony for former teammate Peyton Manning.

The Broncos did receive some good news on the injury front, as Justin Strnad returned to practice after missing Saturday's session due to cramps.