Re: 3rd down back
Needs to be a jack-of-all trades, and usually is more of an open-field runner type, since he's likely to be out in space. Bettis would NOT be an ideal 3rd down back...
Also, I don't think these guys are usually up to the task of carrying a full load...not 300 carry-type guys.
Official Steelersfever Arians Nuthugger