What position did Emmitt Smith primarily play?

What jersey number did Walter Payton wear with the Bears? What position did Barry Sanders primarily play? Which college was Barry Sanders playing for when he entered the NFL? What jersey number did Barry Sanders wear with the Lions? Which college was Emmitt Smith playing for when he entered the NFL? What jersey number did Emmitt Smith wear with the Cowboys? What position did Eric Dickerson primarily play? Eric Dickerson is best known for playing with which NFL team?