The Bills' posted running back depth chart lists Singletary behind Frank Gore and ahead of T.J. Yeldon.
That said, with LeSean McCoy no longer in the picture, Singletary is poised to be a big part of the team's rushing attack this season and carries the most upside of the three backs, who are now in line to work as a committee out of the gate this season, per the team's official site. As is the case in any time-share, a "hot hand" approach could tilt things toward one back or another, but while Gore's status as an experienced veteran probably helps his case early on and certainly gives him any depth-chart tiebreaker for appearance purposes, we'd expect Singletary's responsibilities to grow as the season progresses. There's also a chance the speedy, shifty Singletary may be used on kick returns as well.