Spencer started 14 games for the Bears last season and both games this season, but Chicago will now turn to Rachal in an effort to improve their offensive-line play. Rachal signed with the Bears this offseason after spending the last four seasons in San Francisco.
"I need to just seize the moment and take advantage of it," Rachal said, according to ESPN.com. "The team called my number and that's what I'm here for, to help anyway I can."
Spencer, who has started 86 games during his eight-year career, took the demotion in stride.
"I guess they have to do what's best for the team, and I have to keep working and get better," Spencer said. "I'm a veteran, and I've been around a long time. I understand the process. All I can do is come out here and focus on what I have to do."