Cowboys C Travis Frederick (illness) was placed on injured reserve.
Frederick has not played this season after being diagnosed with an autoimmune disorder in August.
He had not missed a game since being drafted in 2013. From then until 2017, Dallas averaged 5.7 yards per play. This year, the Cowboys are averaging 5.4 and while his absence is obviously not the sole reason for this decline, it does not help.
Source: Adam Schefter, ESPN