McDermott was put in a hard situation this past season, as superstar linebacker Luke Kuechly missed six games because of a concussion, and All-Pro cornerback Josh Norman left via free agency during the offseason.
McDermott interviewed with the team for the second time within a week on Wednesday, reportedly meeting with the Pegulas at their home in Boca Raton, Florida.
The Bills restructured the quarterback's contract in August, giving him a five-year extension while retaining the right to opt out of the deal by March.
In Buffalo, he will be tasked with breaking the NFL's longest active playoff drought (17 seasons) and reviving a defense that ranked 19th in each of the past two seasons. The Bills went 8-8 in his first season, marking just their fifth non-losing campaign during the recent stretch. His Super Bowl experience is another plus.
In 2015, McDermott led a Panthers defense that ranked sixth in the National Football League in both points against and yards allowed en route to representing the NFC in the Super Bowl.
McDermott has been in the mix for several head-coaching positions over the past several seasons.
Carolina finished 21st in yards allowed, giving up 500-plus yards three times. If the Bills land McDermott, Mike McCoy has often been linked as a potential offensive coordinator. The Panthers also lost their top defensive back and one of the best in the NFL, Josh Norman in prior to the season.
Wilks, 47, interviewed for the Los Angeles Rams' head coaching vacancy last week and also had drawn interest from Washington for its defensive coordinator opening.
It's uncertain whom McDermott will hire to oversee Buffalo's offense.