The Bears' defense gets another chance Sunday to show it can stop the run against an opponent that hasn't run the ball very well.
Last week it didn't work out in a victory over the Ravens, who came in with a run game that was one of the worst in the league, but they still pounded the Bears for 174 yards on 41 attempts. The Rams, Sunday's opponent, are a tad better on the run but not by much. They're 22nd in rushing yards and 25th in average gain per run.
The Rams' run game has gotten a bit of a boost from chunky rookie Zac Stacy, a fifth-round pick from Vanderbilt who had back-to-back 100-yard games in Weeks 8-9 and is second among all rookies this year with 537 rushing yards.
"He bounces off tackles," Bears coach Marc Trestman said. "We've got to wrap him up. He's a relentless runner. He's very impressive. He's a little bit like (Ray) Rice in some regards."
The Ravens' Rice had his best day of the season last week against the Bears, rushing for 131 yards on 25 carries for a 5.2-yard average. He came in averaging just 2.8 yards per try.
The Rams started 1-3 with Daryl Richardson as their starting running back averaging 3.1 yards per carry. But with Stacy, St. Louis is 3-3 and, since his first start in Week 5, he's fifth in the NFL with 533 rushing yards.
"Every week, every team is going to have great backs and good running games and an excellent scheme and things like that," said Bears defensive coordinator Mel Tucker, who is once again without five starters because of injuries. "We just have to do our jobs. Nothing's really changed.
"We want to make sure we fit the run properly, do a great job tackling, get guys to the ball and just reduce those explosive runs."
Rice had a 47-yard run to set up the Ravens' first TD and 3 other runs longer than 10 yards. The Bears also allowed 5 runs longer than 15 yards against the Packers and 8 runs of 10 yards or longer in their loss to the Redskins. Reggie Bush had 9 runs of longer than 10 yards in 2 victories over the Bears.
Without his top three tackles and two starting linebackers, Tucker has tried to fill holes in the starting lineup with rookies and former backups.
"With the new players, we just ask them to step up and do what they're asked to do," Tucker said. "We have a scheme. It's about teaching, motivating and developing players. So it's next man up. We work with them on the field and off the field to prepare them to go out and perform for us. We have to work hard to get better. We're not where we need to be right now."
Tackle Stephen Paea is out this week with a turf toe, but Shea McClellin is back at left end after missing two weeks with a hamstring injury.
"We've got to play with the guys that we have," said right end Julius Peppers, who had 12 tackles and 2 sacks last week. "We can't sit around and worry about who we don't have. Hopefully we'll get healthy sooner than later. The guys that we have playing this week will do just fine."
Rookie Jon Bostic makes his fifth start at middle linebacker in place of injured veteran D.J. Williams. In his first four starts he has 30½ tackles, second on the team to veteran weak-side linebacker James Anderson, who has 31½.
"He's playing faster," Tucker said of Bostic. "He's becoming more comfortable in what we're asking him to do. He's gaining confidence in our scheme and where he needs to be."
Bostic, and the defense with its revolving door of contributors, are all in the same boat.
"It's a work in progress with him and with the defense as a whole," Tucker said. "He's a young, ascending player that we're asking to get better.
"There is progress being made (on defense), but it's not where we want it to be right now."
Containing the Rams' run game Sunday would be a step in the right direction.
• Follow Bob's NFL and Bears reports on Twitter @BobLeGere.