I think he only loses carries if he gets hurt. Zorn is old school, and believes in a one back in charge type system. He will run Portis into the ground. So....having Betts as his handcuff would probably be a good idea....cause you know the wheels will fall off sometime soon.
Add to this the fact Zorn is locked on Campbell at QB...and teams will scheme to take away Portis to force Campbell to win games...and I am not all that high on him. Still, if you can hold off til late 2nd or early third....he could be a steal.