ENGLEWOOD, Colo. -- The Denver Broncos were poised to put Devontae Booker right in the middle of the competition with C.J. Anderson to be the team’s No. 1 running back. And then Booker was moved to the physically unable to perform list Thursday ahead of surgery Friday to repair a wrist fracture.

Booker is expected to miss six weeks, and while that means he could be back before the start of the regular season, it also means what was one of the Broncos' most competitive position groups now presents a little short-term opportunity.

Booker had pushed Anderson enough during the offseason program that Denver's plan was for the duo to split carries with the starting unit and essentially see what happened. That plan has been scrapped, leaving Anderson front and center and uncertainty about the order of the depth chart behind him.

"I think I did some things this offseason that were introduced to me, and whether I liked it or didn’t like it, I just kept going with it and kept pushing," Anderson said after Thursday’s practice. "I didn’t do something for two weeks and then stop. I just kept going with it throughout the entire offseason. I’m definitely in the best shape I’ve been in in a very long time, so I’m excited about that."

Because the Broncos will regulate Jamaal Charles' work during preseason due to his knee troubles over the past two seasons, the Broncos did move quickly to add some depth after Booker's injury came to light. Stevan Ridley went directly from an afternoon workout with the Broncos to a one-year contract, and he was in uniform for the team’s walk-through.

Ridley, 28, played in just one game last season -- with the Atlanta Falcons -- and had been waiting for his phone to ring as an unsigned free agent.

"Excited for the opportunity, very thankful and fortunate they gave me a shot to come in and compete," Ridley said. "... I’m a little bit behind, I’ve got a little bit of work to do."

Ridley rushed for 1,263 yards and 12 touchdowns with New England in 2012, the same season he had a 151-yard game against the Broncos. He figures to be in Denver's rotation as soon as the Broncos can get him acclimated to their offense.

"I don’t really care what my role is," Ridley said. "They’ve got some talented guys in there. ... I’m just excited to have an opportunity to get back on the field."

But Booker’s injury will cause some adjustment in how the Broncos work in practice in the coming weeks. Coach Vance Joseph has made no secret of his intention to go easy with Charles to make sure the 30-year-old can contribute when the regular season begins.

It could be a chance for rookie De'Angelo Henderson, veteran signees Bernard Pierce and Ridley and Juwan Thompson to get a few more practice carries and carve out a role in what is still one of the most crowded spots on Denver's depth chart. Upon Booker's return, the Broncos will be ready to reinsert him into the offense because of how much they liked his work in the offseason program as well as how hard he pushed Anderson.

"It’s definitely disappointing for him," Anderson said. "We have a job to do out there, and when he comes back, his spot will definitely be warm and ready for him."

"[Anderson is] in great shape," Joseph said. "He’s probably in the best shape he’s been in three or four years, and that’s important for him. But it’s a crowded room and iron sharpens iron, so he understands that Booker is a good young player along with Jamaal, and we’ve got De’Angelo Henderson as a young draft pick. It’s a competitive room and that should push all of those guys to get better."