ENGLEWOOD, Colo. -- **Guard Ron Leary, nose tackle Domata Peko Sr., quarterback Paxton Lynch and defensive end Derek Wolfe were all ruled out for Sunday's game against Miami, Head Coach Vance Joseph announced after practice Friday.
With Leary out because of a back issue, second-year veteran Connor McGovern will make his first regular-season start in place of Leary at right guard.
"For a young guy to have his first start, it'll be fun to see," Joseph said. "He's worked hard. He played good in preseason. He played good in spot play this year. To have a full game to play against good competition -- [Miami's] Ndamukong Suh and Jordan Phillips, top-notch defensive linemen -- it will be fun to see."
Peko missed a third consecutive practice and will stay in Denver to focus on his recovery from a sprained knee ligament suffered late in last Sunday's loss at Oakland. The injury will snap his streak of consecutive starts at 123 games.
"All week I was trying to be positive with it, but just running around [Thursday] and in the pool [Friday] just jogging, I felt that my knee wasn't stable," he said. "Being in the trenches, you can't have a bad wheel. You've got to be 100 percent in there.
"I don't want to go out there [at] 75 percent and someone will fall into me. That's not going to do us any good. So I just want to get back to 100 percent and start doing my job."
Wolfe is sidelined for Sunday, but no determination has been made on his status beyond this week, Joseph said.
Lynch has a high-ankle injury and is expected to miss another one to three weeks.
With Peko and Wolfe out, Zach Kerr and Shelby Harris are expected to start at nose tackle and defensive end, respectively. Kyle Peko will see rotational work, and outside walker DeMarcus Walker could swing inside and provide depth at defensive end if needed.
Kerr will receive his first start as a Bronco after playing his best game of the season last week at Oakland. Defensive Coordinator Joe Woods attributes Kerr's improvement to the coaching of Defensive Line Coach Bill Kollar.
"Bill grinds him to a nub. He's never been coached like that," Woods said. "I think it just finally came out of him. Each day, I sit down and I watch tape with the whole team Wednesday and Thursday. He's running past everybody, so he gets it. I think the light finally clicked for him. He played outstanding for us last week. He needs to continue to do the same thing. He's been a good surprise for us."
The Broncos' on-field preparation for the Dolphins is underway. (Photos by Gabriel Christus unless noted)
Tight end Jeff Heuerman is questionable because of a knee injury, while Walker, outside linebacker Shane Ray and inside linebacker Todd Davis are all questionable due to illness.
"It's obviously spreading fast," Joseph said of the illness. "We've got to be smart with everybody."
Davis and Walker did not practice Friday. Ray was on the practice field without a helmet. He said after practice that he expects to play Sunday.
"I'm going to play," Ray said. "A couple of more days of rest and some good fluids, I should be all right."
Joseph also announced that Donald Stephenson would start at right tackle. Allen Barbre has started the last three games there in place of the injured Menelik Watson. Stephenson has recovered from a calf injury that he suffered three days before the Week 7 loss to the Los Angeles Chargers.