LAKE FOREST, Ill. -- The Chicago Bears held out starters Chris Harris and Lance Louis from Friday's practice, along with backup running back Marion Barber, who is expected to be inactive for the second consecutive week.
The team's decision to hold out Harris and Louis casts doubt about their availability for Sunday's game against the New Orleans Saints. Bears coach Lovie Smith said injured receiver Roy Williams (groin) "is getting a little bit better," adding, "We'll see how it goes."
The official injury report lists Harris, Louis and Barber as doubtful for Sunday's, while Williams is questionable.
"Three guys: Marion Barber, Chris Harris and Lance Louis didn't practice," Smith said. "It's never good when guys don't practice. The other players all have injuries right now."
Louis (ankle) and Harris (hamstring) sat out the entire week of practice, while Barber (calf) returned in a limited capacity on Wednesday, before experiencing soreness significant enough to put him on the shelf for the remainder of the week.
If Williams can't play, third-year veteran Johnny Knox will take on his repetitions at the "X" receiver. Chris Spencer will sub in for Louis at right guard, according to a source, and Kahlil Bell is expected to step up in Barber's place as the primary backup at running back to starter Matt Forte.
Williams, who assumed the starting job over Knox during training camp, strained his groin muscle in the fourth quarter of the club's 30-12 win over Atlanta on a 13-yard reception near the sideline. Spencer played the majority of last week's contest after Louis sprained his right ankle.
Bears offensive line coach Mike Tice said Louis "put five guys on the ground in 20 plays" before sustaining the injury, and also lauded the play of Spencer, who was originally signed as a backup center to Roberto Garza.
Barber, meanwhile, practiced sporadically and in a limited capacity ever since injuring his left calf in the first half of the team's Aug. 27 preseason loss at Tennessee. The club expressed optimism about a possible return against the Saints, but the running back experienced a setback earlier in the week.
Harris said he's "feeling a lot better, it's a day-to-day injury."
"Hamstrings they can be tricky, but it's nothing major," he added.
New acquisition Brandon Meriweather could take over for Harris at free safety.
"He's obviously a veteran who has played on a very high level for some very good teams," Bears secondary coach Jon Hoke said of Meriweather. "He's been able to pick it up, and understand what we're doing. It's the nuances he's still getting used to and those types of things."
The Bears signed Meriweather just a day after he was released by the New England Patriots, and immediately put the two-time Pro Bowler through a crash course in Smith's Tampa-2 scheme.
With Harris sidelined during practices, Meriweather took reps with the first team at free safety, opposite Major Wright, who played snaps at strong safety.
"I'm OK, getting better by the day, getting more comfortable," Meriweather said. "I'm not focusing on anything else other than trying to learn my playbook. Football is football. You just have to go out there and play, and get comfortable by doing that."
Smith, Hoke and defensive coordinator Rod Marinelli also discussed the possibility of giving rookie Chris Conte playing time in what might turn out to be a rotation at safety if Harris is unavailable.
"Right now, we're just working them all," Marinelli said. "We've got four guys back there."
Michael C. Wright covers the Bears for ESPNChicago.com and ESPN 1000. ESPNChicago.com's Jeff Dickerson contributed to this report.