Most of the time, the left tackle is an offense's best pass blocker. Likewise, for the defense, the right defensive end is usually the best pass rusher.
This is likely due in part to the fact that most quarterbacks in the NFL (and really any level) are right handed, meaning the left side is their blind side.
So, it makes sense for a defense to put its best pass rusher on the quarterback's blind side, simply because the quarterback will have a more difficult time seeing him coming.
But when there's a southpaw taking the snaps, like Michael Vick will be doing for the Eagles this Sunday, the roles are clearly reversed.
Now, instead of Jason Peters protecting Vick's blind side, it's going to be Winston Justice.
But before you get worried, don't forget that Justice has done this before.
He was the right tackle at USC while Matt Leinart, a lefty, was the starting quarterback, and that was clearly not by accident; he was placed there because then-USC head coach Pete Carrol felt Justice was his best pass blocker, and thus the guy he trusted most to protect Leinart's blind side.
Justice's time as a right tackle at USC is what gave the Eagles the confidence to move him to left tackle in the NFL, as they thought his ability to protect Leinart from the right would carry over in a transition to the left side.
But, of course, six sacks by Osi Umenyiora later, we all saw how well that worked out, so that idea was scratched.
At first, I just thought his footwork wasn't quite good enough, but he's displayed excellent footwork while playing on the right side again. This would lead me to believe that he just wasn't comfortable with the left side, which threw off his timing, rhythm, and footwork.
It will be interesting to see how the Detroit Lions attack this. They could move Kyle Vanden Bosch, their best pass-rusher, to the left side in an attempt to attack Vick's blind side, but that would leave either Turk McBride or rookie Willie Young matched up against Peters.
With Cliff Avril out, it's essentially a lose-lose for the Lions, and they will likely have to rely heavily on the blitz to get any kind of pressure.
So even if Peters has a bad game, Vick should be able to see the pressure coming and be able to escape it. But if Justice regresses and has a bad game, it could mean a total disaster for Vick, the offense, and the entire team.
Justice should be just fine, but it's definitely something to watch for on Sunday. That is, if you can take your eyes off of Vick for a second.