Rivera had previously been in charge of the Bears defense since 2004 and had improved dramatically during his tenure there .
I 'm not sure of why , but former coordinator Ron Rivera was not retained by Lovie Smith following Chicago 's run to the Super Bowl in 2006 .
Rivera had previously been in charge of the Chicago defense since 2004 and had improved dramatically during his tenure there .
I 'm not sure of why , but former coordinator Ron Rivera was not retained by Lovie Smith following Chicago 's run to the Super Bowl in 2006 .