There's no way that we can replace the left side departures. Having lost possibly the best offensive lineman of all time in the way of Nelson, and an excellent player in the way of McGlinchey, basically means that there will be a dropoff this year, regardless of who replaces them.
I still believe that the line will be at least decent this year, though. You have Mustipher, Bars, and Kraemer, who started quite a few games, plus Hainsey (who also stared some), coming back, along with Lugg and Ruhland ready to play. It's not as if we're throwing undeveloped, inexperienced players to the wolves like we did in 2007.