BC suffered a ruptured Achilles, so it's kinda difficult to envision him as a more important signee than Corbett at this point. Although it's easier for linemen to return because they don't have to jump and make a lot of cuts, it isn't a guarantee. Even less so at 100 percent. I have read that it would probably take at least two years for him to even return to his old self (again, if he does).
As always, hope for the best, but prepare for the worst.