Either Benhart just isn't ready yet OR we really want this to be a redshirt year (no more than 4 games played) for him. Forbes is not who I would have guessed would be next in line at Tackle after Bando, but good for him.
Benhart himself said that he needs to get a lot stronger. I'm guessing that they would prefer to keep this as his RS year and allow him to develop more, unless that absolutely need him.