One of the most respected teachers of offensive line play in football, Bill Callahan oversaw a Cowboys’ rushing attack in 2014 that turned out to be one of the best the NFL has seen in recent memory. Behind an athletic, young front five, DeMarco Murray ran for a league-leading 1,845 yards. Caught in the right sort of mood, Callahan would probably tell you Murray could have had several hundred more yards. The run blocking in Dallas was that good. Now Washington is counting on Callahan’s magic to get the team back in contention in the NFC East.