After center Dan Koppen suffered a season-ending injury in Sunday’s practice, quarterback Peyton Manning worked with Manny Ramirez in training camp on Monday.

Ramirez, a five-year veteran from Texas Tech, made 11 starts at right guard for the Broncos last season.

Koppen, who took over at center last year after an injury to J.D. Walton, tore his anterior cruciate ligament in his left knee on Sunday.

Ramirez was the starter at center during spring practices before the team re-signed Koppen.

“It doesn’t matter if you’re the starter or not, you’ve got to go in with the mind set that you are, just because you’ve got to be prepared for the type of situation we’re in right now,” he said.

Ramirez said he learned from watching and talking to Koppen and that he had a good relationship with Manning.

“There’s things I still need to work on in terms of footwork and technique,” Ramirez said. “I just have open ears and need to be willing to listen and absorb his knowledge.”

Fox said he had faith in Ramirez, despite his lack of time spent at center.

“You get punched in the gut when any player gets hurt, but we’ll be all right,” Fox said.

Rookie defensive tackle Sylvester Williams left the field during Monday’s practice after suffering a knee injury. He left the field limping but without assistance, and an MRI after practice Monday came back negative. He is expected to miss a day or two of practice.

Defensive end Robert Ayers left practice with a hamstring issue, and tight end Jacob Tamme was pulled out with a quad injury.

C.J. Davis, a guard-center who was held out of Sunday’s practice with an ankle injury he suffered Saturday, returned to the field. He worked as a center with backup quarterback Brock Osweiler.

Defensive end Derek Wolfe also returned to practice after missing Sunday.

Steve Vallos, who was signed as a free agent after Koppen’s injury, joined practice for the first time. He spent time at center during offensive line drills and worked with the team’s backup quarterbacks later in practice.

“It’s a lot of new words, new technology, new people,” Vallos said. “I’ve had some of the same coaches, so concept-wise there is a lot of carry over.”

The competition at running back appeared to remain open, as Ronnie Hillman, Montee Ball and Knowshon Moreno all took repetitions with the first team. Ball had the biggest run in the early going.

The offense remained sharp early in practice, with Manning targeting Eric Decker and Demaryius Thomas in the opening drills. Thomas provided a highlight of camp with a leaping touchdown catch during two-minute drills.

Defense tackle Kevin Vickerson provided a defensive highlight when he blocked and almost intercepted one of Manning’s passes.

The team will have a walk through tonight before a day off on Tuesday.

Caitlin Swieca: 303-954-1297, cswieca@denverpost.com