Trent Williams said this week that he didn’t expect to play again unless there was an emergency situation in the final two weeks of the season. If the Redskins do run into such a predicament at left tackle, they’ll have to break a different pane of glass to address it. Coach Jay Gruden said on Friday that Williams will go on injured reserve as a result of the knee injury that’s bothered him for most of the year and will require surgery to repair.