I happened to be watching NFL films tonight and they showed when the Fridge was a short yardage back for da Bears. He did pretty well as a rookie. 2 TDs in 5 carries, for 7 yards, and at least one of those non-TDs was from well outside the goal line. Plus he caught a TD pass.
So I wondered why they didn't keep using him that way. For the rest of his career, Perry carried 3 times, lost 2 yards, never gained positive yards, and fumbled twice.
I still remember being p.o.'d that Perry got a TD in the Super Bowl while Payton watched. Payton deserved that one. Payton was also one of the more effective short yardage carriers because he hit the hole quickly, and could leap over the line, or dart to an opening.
More important than the back is getting the push from the line.