All players don't have the same impact on a game. It's not at all a crutch. Center on this team is the second most important position because of what he does and is the most difficult to replace unless you have a very experienced backup. We simply don't have someone who can do it remotely as well as he does at this point. It comes with the territory, pretty much all offenses losing their center are going to see a significant drop-off in OL play.
We didn't make zero moves though. Maybe you slept through the off-season,