Dixon worked out for the Bills over the weekend along with free-agent quarterback Pat White, coach Doug Marrone said, but neither was immediately signed to the active roster. Instead, the Bills promoted Thad Lewis from the practice squad to start Sunday against the Cincinnati Bengals.
However, the Bills will now have Dixon on their practice squad, adding another layer to one of the volatile quarterback situations in the NFL. Dixon was a fifth-round pick of the Pittsburgh Steelers in 2008 who has three career starts.
The Bills also made several changes to the back end of their 53-man roster. They signed linebacker Ty Powell off the New York Giants' practice squad, signed cornerback Brandon Smith off their own practice squad and waived linebacker Marcus Dowtin and cornerback Johnny Adams.
Powell, who played at Harding, was a seventh-round draft selection of the Seattle Seahawks this season. At 6-foot-2, 249 pounds, he will likely contribute to special teams for the Bills.
At 6-1 and 205 pounds, Smith is the largest defensive back on the Bills' roster. An undrafted free agent in 2011, Smith was out of football last season before joining the Green Bay Packers for their most recent training camp.
Dowtin and Adams both were special-teams contributors for Buffalo.