Air carrier tug driver pushing a B737-800 back onto the DEN ramp area reported he had to stop abruptly to avoid a collision with a regional jet taxiing past.

Narrative

I was the pushback driver for [this] flight. The pilot communicated that the brakes were released and that I was cleared to push. I relayed [hand] signals to my wing walkers; in turn they gave signal I was clear to proceed. A few seconds into push; one wing walker signaled for me to stop the push. I brought the aircraft to a complete stop. Within seconds of coming to a stop; an RJ passed directly behind our aircraft on the green taxi line. Had my wing walker nor I not been alert; the chances of an aircraft on aircraft collision were great; perhaps certain.