Starting running back Terrance West is sidelined indefinitely with a calf issue. Guard Matt Skura also is out with a sprained MCL and Baltimore now is forced to start its third different player at right guard this season.
Defensive tackle Brandon Williams is still unable to practice because of a foot injury, and Jimmy Smith is hampered by a sore Achilles.
Nonetheless, Ravens head coach John Harbaugh is confident the team has enough depth to absorb those losses. However, the constant rotation of players has already disrupted some of the team's continuity, especially on the offensive line.
"It just doesn't matter. It is not something we think about," Harbaugh said about the injuries. "It is not something we quantify. We don't waste any energy thinking about that. You just go and get ready for the next game."
Despite the injuries, the Ravens' offense should be playing with some added confidence, especially with quarterback Joe Flacco looking much more comfortable in the pocket and throwing the ball downfield. Mike Wallace is also starting to become a bigger threat in Baltimore's offense with his ability to run past opposing secondaries.
For added depth, the Ravens signed Bobby Rainey to support the other two healthy running backs -- Alex Collins and Javorius "Buck" Allen -- on the active roster.
The goal for the Ravens (3-2) will be to start fast against the Bears (1-4) and make them play from behind with rookie quarterback Mitchell Trubisky. Flacco said the team understands the opportunity in front of them, especially being tied for first place in the AFC North.
"We definitely want to make sure we come out swinging in this game, just like we did last week," Flacco said. "It was definitely a step in the right direction. I think we're a confident group. But you have to go out there and play well and prove yourself all the time."
Defensively, the Ravens sorely missed Williams, their best run-stopper. Without Williams in the lineup for the past three games, Baltimore has allowed 447 yards on the ground. Baltimore lost two of those games.
That unit will face another big challenge against the Bears and running back Jordan Howard, who is 10th in the league with 328 rushing yards with four touchdowns.
"The NFL season is a marathon," linebacker Terrell Suggs said. "You have to handle your games and what you can do. I think in years past, that was our mistake. We were worried about what everyone else was doing.
"Every Sunday you get a chance to control your own fate. We just have to worry about the team that's in front of us. We just have to run our race."
SERIES HISTORY: 6th regular-season meeting. Bears lead series, 3-2. The teams have not played since Nov. 17, 2013, when host Chicago escaped with a 23-20 overtime victory. Prior to that game, the Bears and Ravens split their meetings with the home team winning each time.
--Ravens cornerback Jimmy Smith is one of the team's most talented players when he is healthy.
However, he has battled injuries throughout his career. The latest setback is a sore Achilles that has mostly kept him out of practice for the past two weeks. Smith was able to play seven snaps in Week 5 against Oakland and managed to recover a fumble and run 47 yards for a touchdown.
The Ravens spent the offseason adding depth to the secondary. When Smith couldn't play, rookie Marlon Humphrey effectively stepped into that role. Ravens head coach John Harbaugh, though, said the team is better with Smith on the field.
"We just have guys that we can play," Harbaugh said. "We are very good with the guys that we have. We want Jimmy out there. He is a top-notch corner. I think he is one of the best corners in football. I am a big Jimmy Smith fan. I think Jimmy will prove in the next couple years to be maybe the best, maybe the best. I think he has a chance to do that. I feel that strongly about Jimmy."
Baltimore is second in the league with nine interceptions behind Jacksonville (10).
--The Ravens' running game took a hit when Terrance West injured his calf against the Raiders and is out indefinitely.
For added depth, the team signed Bobby Rainey to support Alex Collins and Javorius "Buck" Allen, who have been splitting carries. Baltimore is yet to have a 100-yard runner in any of its games this season. Nonetheless, the Ravens are ranked fifth in the NFL with 653 yards.
The running back-by-committee approach seems to be an effective strategy this year. Ravens head coach John Harbaugh has been impressed with his undermanned group of running backs.
"The running game came through when it had to," Harbaugh said. "That just goes to show you that techniques were really good and the effort and tenacity, the physicality - it was definitely there. We were strong at the end of the game. That is a statement for our guys."
NOTES: RB Bobby Rainey was re-signed after Terrance West suffered a calf injury in Week 5 against Oakland. Rainey spent the entire preseason with the Ravens, but did not make the final roster. He ran for 42 yards on nine carries and a touchdown in the final preseason game against the Saints. Rainey also began his career with the Ravens as an undrafted rookie in 2012. ... DE Kapron Lewis-Moore, a sixth-round pick by Baltimore in the 2013 draft, was signed to the practice squad. Lewis-Moore played four seasons in Baltimore, but was limited to five games because of injuries. He later signed with the Bears before being waived after this preseason. ... C Derrick Nelson, a 6-foot-3, 295-pound rookie out of Rutgers, was signed to the practice squad for depth. The Ravens' offensive line has already been decimated with injuries this season, including the loss of guard Matt Skura with a knee injury Sunday against Oakland. ... DT Brandon Williams was still unable to practice Wednesday after missing his third straight game with a foot injury. With Williams out of the lineup, Baltimore has struggled against the run, allowing 447 yards on the ground over the past three games. Ravens head John Harbaugh would not provide a timeline for when Williams might return. ... DL Carl Davis was able to practice Wednesday after suffering a hamstring injury Sunday against Oakland. His status for Week 6 against the Bears is uncertain. The Ravens are already missing Brent Urban (foot) and Brandon Williams (foot) on the defensive line. ... TE Maxx Williams (ankle) was back at practice Wednesday. He suffered the injury in Week 2 against Cleveland and had not played or practiced since. Williams has five catches for 26 yards this season.