“Kathryn Smith has done an outstanding job in the seven years that she has worked with our staff,” Bills head coach Rex Ryan said in a statement of Smith, who also worked with him at his previous team, the New York Jets.

“She certainly deserves this promotion based on her knowledge and strong commitment, just to name a couple of her outstanding qualities, and I just know she’s going to do a great job serving in the role of quality control-special teams.”

Ryan said he had consulted Arizona Cardinals head coach Bruce Arians, who hired a female linebackers coach during a training camp last summer.

Ryan also cited the decision by National Basketball Association (NBA) powerhouse San Antonio Spurs to appoint a female assistant coach as evidence that the profession was no longer an exclusively male bastion.

“You can see the success some of these young ladies are having in the coaching profession… and realise how exciting this is for women like Kathryn Smith as well as the Bills organisation,” he said.

Smith, who will enter her 14th year in the NFL next season, spent 2015 as administrative assistant to the head coach at Buffalo. Before that, she spent 12 seasons working for the New York Jets, where she started as an intern in 2003.

Ryan recently completed his first season on the job in Buffalo, compiling an 8-8 record that included two wins over the Jets, where he was head coach from 2009-14. (Reporting by Andrew Both in Cary, North Carolina; Editing by John O’Brien)