Who would be better in the NFL RIGHT NOW: Tiki Barber vs. Herschel Walker

I just had a great tweet hit my timeline, and since it's a slow news day I figured this would be appropriate despite having nothing to do with the Jacksonville Jaguars. (h/t to Mike on twitter)

Both players have expressed a wish and desire to come back to the NFL. So, which retired NFL runningback would be more effective if they were both on a roster in 2011... Tiki Barber or Herschel Walker?

I don't think Tiki Barber can do 1,000 push ups.