Williams left Sunday's practice early with a hamstring issue, BJ Kissel of the Chiefs' official site reports.
Given the tricky nature of hamstring injuries, it's possible the Chiefs are being extra cautious with the running back they listed atop their depth chart going into training camp. Williams averaged 100.4 scrimmage yards and 1.7 touchdowns on 17.5 touches per game over his final six games (including playoffs) last season.