Same reason we kept him on the PS. Same reason the Raiders took him. Yards do not come easy when the whole stadium knows your running the ball. That was 85% of Barber's carries.
2 YPC vs stacked boxes aint bad, its the opposite.
If you gotta cut someone and move them to the PS, then hey... that's football
If you injury designate someone, then you don't have to cut anyone. Somebody will stub a toe/get sick or something within the next week. Problem solved
Short yardage backs usage rate fluctuate wildly. They can have a game where they get 1 touch, or a game where they get 7-10. Many of those looks come against jumbo packages.
As it stands we don't have anyone on the roster or PS anymore who we would want to expose them to, or can reliably physically withstand, the high end of that spectrum of carnage.
Gibby and Thomas can give you a couple, but I'm not taking the crux of my O and ramming them into jumbo packages several times a game. They are too valuable to risk.
Need someone who is capable of absorbing that kind of punishment.