ENGLEWOOD, Colo. --Cornerback Chris Harris Jr. and safeties Darian Stewart and T.J. Ward returned to practice after getting a rest day Wednesday, but fellow defensive backs Aqib Talib and Kayvon Webster remained sidelined as the Broncos opened their Thursday on-field work.

Talib traveled to California to seek a second opinion on the back issues that have plagued him the last week. He has not been ruled out for Sunday.

"I got good vibes from what 'Greek' [head athletic trainer Steve Antonopulos] told me a while ago from the visit," Head Coach Gary Kubiak said. "I know there's some people that have to get together and talk this through, to make sure we know exactly where he's at, so he's on his way back as we speak."

Webster worked with a team trainer on the sideline.

Talib has a sore lower back, while Webster has a hamstring injury. They were joined on the out-of-practice list by center Matt Paradis, who has a hip issue, and left tackle Russell Okung.

Kubiak said he expects to hold Okung out for one practice a week.

"I'll probably choose which day that is depending on what we're doing at practice," Kubiak said. "He'll participate in all the non-full-[practice] stuff, walk-throughs and stuff. You're going to see that from him and Matt probably the rest of the [season]."

Okung practiced Wednesday, while Paradis has not practiced since Oct. 22, although he did play against San Diego on Oct. 30.

Inside linebacker Brandon Marshall (hamstring) and running back Devontae Booker (sore shoulder) also practiced Thursday. Marshall missed the Chargers game, while Booker was briefly sidelined after being hurt in the first quarter before returning and posting 84 yards from scrimmage and a touchdown.