pony backfield
n.— «Childress said it was also possible both players could be on the field at the same time in certain sets. “We could run what’s called a pony backfield,” Childress said. “We did that in Philadelphia (when he was the Eagles offensive coordinator) with (Brian) Westbrook and (Correll) Buckhalter. The chances are pretty good that both of them could find themselves on the field in certain situations.” Spielman said relying on more than one running back seems to be the trend in today’s NFL.» —“NFL Draft: Vikings snag OU’s Peterson” by Frank Rajkowski St. Cloud Times (Minnesota) Apr. 29, 2007. (source: Double-Tongued Dictionary)