Only the 1-9 Jacksonville Jaguars have allowed more rushing yards per game than the Bears, who have been gashed for a whopping 727 on the ground the past four weeks, an average of 182 a game. For comparison, the Jets allow a league-low 73.2 rushing yards per game.
"We've been inconsistent," coach Marc Trestman admitted. "At times we've been able to do very well. And at times we haven't."
In three of the first five games, the defense allowed 80 or fewer rushing yards. But injuries of varying severity to defensive linemen Henry Melton, Nate Collins, Stephen Paea and Shea McClellin along with linebackers Lance Briggs and D.J. Williams have taken their toll.
The Bears have 29 runs of 10 yards or longer, but they've allowed 40, which has resulted in their No. 27 rank in yards allowed per run. Last week Ray Rice bolted 47 yards, although he didn't have a run longer than 14 yards in the Ravens' first nine games.
"It's a constant battle each and every week," Trestman said. "Some teams have gotten some long runs on us, certainly. We saw that the other day. We don't expect that we're going to eliminate it all, we're just trying to get better. We're doing it with new guys and young guys, and we know that.
"That's just where we are. We're not where we would want to be. We're a work in progress, so to speak."
The Rams are 22nd in rushing yards and 25th in average gain per run but have been better of late with fifth-round rookie Zac Stacy replacing Daryl Richardson.
It just gets worse:
Last week Josh McCown was provided excellent protection against the Ravens' pass-rushing duo of Elvis Dumervil and Terrell Suggs -- who never laid a glove on him in the Soldier Field muck.
This week might be tougher on a fast artificial surface against the Rams' defensive ends; Kyle Long's big brother Chris (6½ sacks) and Robert Quinn, who's second in the NFL with a dozen sacks.
"The difference is probably the turf (at the Edward Jones Dome), and the noise in an away game," Bears offensive coordinator/offensive line coach Aaron Kromer said. "Last week, we faced two excellent ends. But when you get in someone's home field and they have the noise and you have to get off (the snap) in the noise, it's a little tougher. Big challenge for us."
Former Bears first-round bust Chris Williams has found a home on the Rams' offensive line at left guard.
Williams' progress with the Bears was frequently derailed by a succession of injuries, starting with a back problem on the second day of his rookie training camp that required surgery. Despite starting 38 games at left tackle, right tackle and left guard, Williams never really found a position that he could hang onto in 4½ seasons. The Bears took him 14th overall out of Vanderbilt in 2008, but he was waived midway through the 2012 season. A week later he was picked up by the Rams. He won the left guard spot this summer and has started all 10 games this year.
"We don't really pay much attention to a player's past," Rams coach Jeff Fisher said. "He's a very talented kid. He's a good, smart football player. I think he just needed a fresh start. He came in and played guard and tackle for us last year and played well. He's familiar with the system now. He's having fun. He's a great guy in the locker room and he's become a great teammate here."
Quarterback Jay Cutler (ankle), linebacker Lance Briggs (shoulder) and defensive tackle Stephen Paea (toe) did not practice. Cutler and Briggs are out for Sunday, and Paea isn't expected to play.
Cornerback Isaiah Frey (hand), safety Craig Steltz (concussion) and defensive tackle Jeremiah Ratliff (groin) were limited. Offensive tackle Jordan Mills (quadriceps), defensive end Shea McClellin (hamstring) and long-snapper Patrick Mannelly (calf) went through full practices and should play.
Two Rams starters, guard Harvey Dahl (knee) and cornerback Cortland Finnegan (eye) did not practice for the second straight day.