No matter how skilled or talented an offense is, it all comes crashing down without proper blocking.
The Rams learned this in Super Bowl XXXVI.
The Patriots learned this again in Super Bowl XLII.
So as the preseason moves into its second weekend, and teams begin looking around at their needs, offensive linemen come to the forefront.
Already, some teams (like the Jets, possibly) are noticing that their current lines might either not be complete or are not completely healthy.
In any case, many veterans are still available in free agency. Here's a look at a few of the best ones (not ranked in a specific order).