Despite Alex Smith remaining asymptomatic of a concussion after taking two significant blows to the head last Sunday, Chiefs coach Andy Reid, with the full support of management, trainers and ownership, opted to sit Kansas City's starting quarterback out this week largely as a precaution, team sources said.

Smith was able to practice vigorously, running the scout team all week, sources said, and all of his cognitive tests cleared him to play. But the club wanted to err on the side of safety and eliminate an unforeseen setback for Smith that would leave the Chiefs shorthanded at quarterback.

While not concussed, Smith did need sutures in his ear after absorbing a direct hit to his head, and he left the game again after a second hit caused significant bruising and discomfort where his helmet impacted his neck area. Given that concussion symptoms sometimes manifest days after the original trauma, Reid, after consulting with others in the organization, decided midweek it was best to declare Smith inactive. Backup Nick Foles could then get all the starting reps and novice Tyler Bray could get additional reps, should he be forced to play.

Privately, the decision was heralded inside the NFLPA as a forward-thinking and proactive approach to potential brain injuries. The initial review of what took place last Sunday, in-game and since, has led the union to see no reason to ask the league for an official review into how the concussion protocol was applied last week, sources said. The union has initiated that process twice this season (for Cam Newton and Tyrod Taylor, with no protocol lapses determined in either instance).

Smith was able to lift weights regularly and work out as he normally would this week, and by Tuesday already had been cleared by an independent neurologist. Reid was in contact with Smith and his family as the team weighed its options. If Smith remains asymptomatic through this weekend, then he will return to starting reps in practice. The Chiefs also expect defensive star Justin Houston back for Week 10; they had long been targeting Week 9 but are going to give him one more week in his return from offseason knee surgery.