Obviously getting Oliver back at 100% would be a huge boost to the LB corps.
I don't necessarily agree we are in trouble though if Oliver isn't able to play at a high level. We have a lot of options at LB and many of them were pretty highly touted coming in and have been in the program now for a few seasons. LB would be a prime position where someone could break out in a big way. Guys like Gordon, Willis, Burns, Lindenberg and others are all potential breakout candidates. For example, Willis and Gordon are both in year 3 now so should be starting to hit the point where they are ready to take on a bigger role.
Too often in football fans assume if a guy doesn't play right away it means they are not good. While that can tend to be true on the basketball side, in football it takes a lot of players multiple years to really get acclimated to the college game and to get to the point where they are ready to make an impact.