The Bills have the second best running attack in the AFC behind the 9-0 Kansas City Chiefs, and Tomlin is more than aware of the threat that they will pose.
Tomlin told Steelers.com: "Yeah those two primary runners. Fred Jackson is awesome.
"He's got great contact balance, vision, and patience. He's not an easy tackle. His yards after contact are really impressive.
"And C.J. Spiller is a guy you have to worry about containing and keeping within the chute of the defense, because any time he gets it he's capable of going the distance."
Both the Steelers and the Bills sit at the bottom of their respective divisions in the AFC.