Singletary (hamstring) has been declared out for Sunday's game against the Bengals, Chris Brown of the Bills' official site reports.
We'll see if the rookie can heal up enough to ply his wares in what looks like a big Week 4 contest against the Patriots, where both teams could be 3-0. In the meantime, Frank Gore and T.J. Yeldon are in line for extra work this week against the Bengals.