Modkins has a long history working with new Bills head coach Chan Gailey. Working on an NFL Minority Coaching Fellowship in 1999, Modkins spent time learning under Gailey while the latter was in his final season as head coach of the Dallas Cowboys. He then worked with him at Georgia Tech in each of Gailey's six years there, coaching running backs and defensive backs. Upon Gailey's firing from Tech, Modkins followed him to Kansas City in 2008, where Gailey became offensive coordinator and Modkins coached running backs. Modkins spent the 2009 season in the same position under Ken Whisenhunt in Arizona.
Gailey told reporters at his introductory press conference that he would be the primary play-caller on game days, so while Modkins will hold the title of offensive coordinator, it's unclear precisely what his role will be. Given his history, it's a safe bet he'll be involved with Buffalo's running backs, however.
Jurecki reports that the Bills requested permission from Arizona to interview Modkins, and after a couple of days, the two sides came to an agreement Friday night.