Sources familiar with the Bills' decision-making process said a lot of weight will be placed on the respective preseason performances of their running backs, with veteran free-agent pickup T.J. Yeldon (formerly of the Jacksonville Jaguars) also theoretically in the mix. The plan, at least when it comes to McCoy, Gore and Singletary, is to give each of the backs an extended look that allows them to get into a rhythm. It may well be that one back will be heavily featured in each of the team's first three preseason games, meaning the competition begins in earnest against the Colts.