LAKE FOREST, Ill. - Although Michael Turner leads the NFL in rushing, the Chicago Bears defense sees someone else when they look at the Atlanta Falcons' No. 33 on film. | NFL page

"He's the modern day Jim Brown, you know what I mean?" Bears linebacker Lance Briggs said. "The guy's physical, he's the NFL's leading rusher, he's a guy who's not going to go down on arm tackles.

"We have to play physical and we have to rally around the ball. It's a great challenge for us. It's an opportunity for us to stop one of the best running backs in the game."

The Bears' fourth-ranked run defense hasn't yet met a running threat like the one it faces Sunday in the Georgia Dome against Turner and the Falcons.

But all-time great Brown?

"I said that, but I didn't come up with that," Briggs said Thursday at Halas Hall. "One of our coaches came up with that."

Linebackers coach Lloyd Lee started comparing Turner to Brown because of a powerful running style, but didn't want the comparison to be made public.

"I want to get in these guys heads that, 'Hey, he's productive. He's good,"' Lee said.

Bears defensive end Adewale Ogunleye compared Turner to someone else.

"He kind of reminds me of when I was playing with Ricky Williams (in Miami)," Ogunleye said. "I remember when (Williams) had his two good years, he was really hard to bring down and his lower body was really strong and he'd run over the secondary a lot. And that's what it looks like Turner is doing."

To most, he is neither Williams nor Brown, but Michael "The Burner" Turner, a 5-foot-10, 244-pound former back for the San Diego Chargers and Northern Illinois who has 543 yards, including 100 or more in three of his first five games after signing a $34.5 million free agent contract with Atlanta.

Turner played high school football at North Chicago High School, five miles from the Bears' practice facility.

"Guys hit him and he stays on his feet and is able to spin off and keep running," defensive lineman Israel Idonije said. "So we have to have that gang tackle mentality, which we have had. We do a good job of swarming and not letting one guy get in a situation where he has to make a tough tackle."

Added Bears safety Mike Brown: "We'll have to bring our big-boy pads."

While the Bears' defense is allowing 74.2 rushing yards a game, no team or single back has challenged them with the running game to the extent they expect from Turner.

The 16 rushing attempts by Philadelphia's Correll Buckhalter is the most a back has made against the Bears. Carolina's Jonathan Stewart had 77 rushing yards, the most given up by the Bears.

The Bears figure their run defense can only get better this week with the expected return of defensive tackle Tommie Harris from a one-game suspension and another missed game due to a sore knee.

Harris went through a full practice on Thursday for the first time since aggravating a knee injury in the Bears' 27-24 overtime loss to Tampa Bay Sept. 21.

Coach Lovie Smith is also concerned about Atlanta's change-of-pace back Jerious Norwood, who averages 6.6 yards per carry.

"Not many players running the ball in the league have that type of speed," Smith said. "He has good size, too, good moves.

"It's a great combination of a speed guy along with a guy that can run with speed and power in Turner, and their stats show it. They're averaging 180 yards a game (180.6), you have to do quite a few things right to do that."

Smith confirmed cornerback Nate Vasher has recovered enough from hand surgery to play Sunday. However, he said backup Corey Graham will continue to see playing time, if not start.

"As we've said, if a player proves he can help us win, there's enough reps for everyone to go around," Smith said. "So hopefully we'll have Nate available, but even with Nate available we plan on still playing Corey Graham."