I think the comment has to do with the questions surrounding our quarterbacks. It was pretty clear that Green was not ready last season - until he comes under fire in a live situation, we don't know whether he's improved enough to be the guy. Lee is a question mark due to the injury. Everyone else in the running - well, the lack of actual game experience is the main factor. I suspect that Bo was commenting on the fact that we're going to have to get many of them into games to determine who will be the guy - and that could take a number of games.
I'm with Nexus on this, though - if the offensive line is good enough, the quarterback position will be fine. Our line has, for the past few years, always seemed to have one breakdown each play - one missed block, etc. Lee, despite any shortcomings, had to run for his life or rush throws too often last year. And we weren't consistent in getting a good push on running plays. All of that's attributable to the offensive line.