Smith (neck) has been ruled out for Sunday's clash against the Chargers, Adam Teicher of ESPN.com reports.
Smith will miss his fifth straight contest due to a neck injury he suffered Week 13 against Green Bay. The offensive tackle was able to practice in full Wednesday but subsequently sat out both Thursday and Friday. It's unclear if Smith suffered a setback or if the team is just taking it easy with him since the Chiefs have nothing to play for Week 18 and are resting numerous starters.