The Cowboys placed Williams (foot) on injured reserve Saturday, Kate Hairopoulos of The Dallas Morning News reports.
Williams' sixth season in Dallas will come to a premature end after he just missed the first game of his career. He was considered a healthy inactive in last week's game against the Lions, but it was later learned he sat out for personal reasons as well as complications from a surgically repaired right foot. The 29-year-old will now set his sights on a 2019 return. He caught just two balls for 18 yards in three games this season.