"The injury, and the fact that Alex had symptoms seven days later, eight days later on a concussion," Harbaugh said. "I've had some bad experiences, not going to put a guy back out there who has symptoms like he had. They were serious enough."
Smith was injured Nov. 11. The 49ers played Chicago eight days later. Smith has been symptom-free since Tuesday, according to comments Harbaugh made Friday.
Doctors cleared Smith on Saturday. Harbaugh made Smith the No. 2 quarterback Sunday. Meanwhile, Kaepernick passed for one touchdown, rushed for another, took zero sacks and helped the 49ers win third down. Smith watched from the sideline and often kept on his helmet, just in case.
"Now, he eventually got cleared," Harbaugh continued, referring to Smith, "but the thought was to rotate him back into the action. But not all the way to the front lines. Thought that would give him a chance to get cleared up completely. That was the rationale."