We all know that Glenn is a very important character in this series. He is even my personal favorite character on the show. But I have not given up hope that he is still alive. As you can see above it appears that Glenn is being ripped apart by walkers. I believe that Glenn is not the one that they are ripping into. We have all seen the episode, but if you watch it again you will see that Nicholas fall and Glenn is holding on to him. My theory is that Glenn fell under Nicholas and that just like in season two, on the highway, Glenn is going to hide under Nicholas's dead body.