It is more significant than people realize. It's a bigger deal for tackles to switch sides than for guards... but still a big adjustment.
Lets say you are right handed and someone tells you that you have to start doing things with your left. That is essentially what an OL does when he switches sides. Your stance, balance, footwork, and hand technique must mirror to the other side. It takes practice to be effective playing on both sides.
This is why you generally should NOT switch up your OL mid-season. Backups generally practice at several positions so they are better suited to be inserted at multiple places on the line. But starters don't get reps anywhere other than their position. That is why having a guy like Snyder on the bench is so valuable. He will be missed.
[ Edited by blm7754 on May 9, 2012 at 7:38 AM ]