Nelson returned kickoffs for a while in 2010, I think. Here is what we learned:

A. Sometime he fumbles when he returns kickoffs. At least Harris and Hyde don't do that.
B. He was never especially explosive returning kicks. Occasionally he got it out around the 40, nothing that Harris or Hyde couldn't do.
C. If Nelson goes down the Packers are in a world of shit, and exposing him on an extra 2-3 plays per game when someone else can do the job just as well would be, well, dumb.