"He's one of the top linebackers in the game," Bears quarterback Jay Cutler said. "He's very active, a lot of intensity, [and] a great tackler with good awareness."
Willis leads the Niners with 86 tackles and two interceptions, and is tied for second on the team with 2.5 sacks.
"Just watching him and coach [Mike] Singletary, they're very disciplined," Cutler said. "They're very sound and will make you beat them. They're not going to go out and beat themselves."
The Bears do catch a huge break since San Francisco will be without starting cornerback Nate Clements. With Clements out for the second consecutive week, Tarell Brown is scheduled to make his third start of the season at cornerback -- perhaps a matchup the Bears could look to exploit down the field.