The reality is, most left guards should grade out higher than right guards.
Most teams are “right-handed,” meaning they often put the strength of the offensive formation to the right side rather than the left. As a result, most slide protections—a zone scheme in which three linemen block two defenders—go to the left, which is customarily the quarterback’s blindside. This means the right guard on most teams has a tougher job because he’s tasked with more one-on-one pass blocking assignments than the left guard. The stats bear this out: In the Pro Football Focus rankings of guards who played at least half of their team’s snaps last season, seven of the top 11 were left guards; 12 of the top 15 tackles also played on the left side.
Until sites like Pro Football Focus become mainstream, the pervading belief will be that you can only tell how an offensive line is playing based on sacks allowed or rushing yards per carry—flawed metrics that suggest you can have a forest without any trees. Whether an offense moves the ball forward and gets pushed backward, football’s forgotten big men are playing a game in which their personal scoreboards change on every play like a stock market ticker.
As someone who started at least five NFL games at both guard positions, I often tell people that I could have played left guard for an entire season and the team would have been fine. Right guard? I would have been exposed as a liability after a handful of games because my one-on-one pass protection wasn’t up to snuff. Then again, you’d never know it by looking at my 2002 grades.