Williams played two series in the Bills' preseason opener last Sunday, and has been limited throughout training camp with a foot injury.
"He keeps getting treatment to take care of his body," Bills coach Doug Marrone said Wednesday. "Again, we're just trying to be smart up and down, resting him for some time, just so he can make sure he just gets ready. Especially coming off this short week."
Williams dressed for the game, meaning he was available to play in an emergency.
Williams joined receivers T.J. Graham (groin) and Stevie Johnson (left hamstring) on the sideline. Also not in uniform were cornerbacks Leodis McKelvin, Justin Rogers and Crezdon Butler, as well as defensive end Kourtnei Brown and offensive lineman Keith Williams.
The Vikings were missing fullback Jerome Felton, who underwent an emergency appendectomy Wednesday and did not travel with the team. Defensive tackle Christian Ballard and cornerback Jacob Lacey also were not in uniform.
Information from The Associated Press was used in this report.