I'm sorry... but there is a reason Antonio Pierce and Khary Campbell haven't earned starting jobs in the NFL in their careers. They are decent enough backups... but no Barrow (and no Mitchell for that matter) opens one more hole in our defense which is suspect enough with our weak D-Line.
EVERY great defense in the history of the NFL had a strong D-Tackle(s) and a strong middle linebacker... Singletary and Ray Lewis pop to mind off the bat....
You can have a secondary that is only slightly above average if you are pressuring the QB and stuffing the run to force the team into long passing situations... that's what worries me about this unit, just like the ones we've had for years now... the Rams REALLY exploited our weakness (T. Holt - 143 yds in one half!!) last game and I am afraid unless we find SOMEONE on the D-Line and Middle Linebacker to step up big time... we might have to get used to what we saw...
Personally, and I know I don't know as much as our coaching staff of course, but I'd take Mitchell over Pierce any day... he was a good run-reader and stuffer. We have enough speed with LeVar and Washington, we needed K-Mitch's experience and run stopping abilities... although I hope I have to eat my words