When the Dallas Cowboys take the field against the Kansas City Chiefs on Sunday afternoon, all eyes will be on Dak Prescott and Patrick Mahomes. It's what will happen in front of the former that might raise some eyebrows though, with the Cowboys looking to make a change on their offensive line they hope will give them a better chance at stealing a victory at Arrowhead Stadium. Connor Williams, the team's resident starter at left guard, will be replaced by Connor McGovern, a talented former third-round pick who has been quietly improving in the background; and in a game that will likely see the return of All-Pro left tackle Tyron Smith.

The swap at left guard is a significant development for the Cowboys, and particularly for Williams, who is playing in the final year of his rookie deal and entered the 2021 season hoping to increase his value in Dallas. Instead, Williams was forced into a preseason experiment at center that was a complete failure before being moved back to left guard -- playing mostly well to this point. 

His Achilles heel, however, has been penalties that have routinely either killed drives and/or put the Cowboys offense in position to nearly lose critical games (e.g., in Week 6 against the New England Patriots). To date, Williams has been flagged for 10 penalties for a total of 110 yards, league high numbers in both categories, eight of them being holding calls. For contrast, his 10 flags are more than twice as much as center Tyler Biadasz (4), who is in only his second NFL season and four more than Terence Steele (6), who is also in only his second year and despite having been thrust into the starting role at right tackle during the five-game suspension of La'el Collins.