We'd better hope Lewis stays healthy. If he's not, then moving a midfielder back might be our best option. Berhalter is simply not good enough to play in the World Cup. I actually like Bocanegra a lot more than other people seem to, but he isn't great at LB anyway, and if he's not completely fit, he shouldn't be put in the position of trying to do the extra running that our outside backs do.
Crazy thought: didn't O'Brien play some left back at Ajax? What about Convey? He's a little short to be a defender, but is he capable of playing back there in a pinch?
I used to think we had plenty of good defenders, but I'm just not comfortable with players like Berhalter, Conrad, and Albright against Czech and Italy.